{"id":416380,"date":"2025-12-06T20:28:55","date_gmt":"2025-12-06T19:28:55","guid":{"rendered":"https:\/\/climatescience.press\/?p=416380"},"modified":"2025-12-25T01:09:06","modified_gmt":"2025-12-25T00:09:06","slug":"canada-summer-daily-low-temperature-trends-1900-2023","status":"publish","type":"post","link":"https:\/\/climatescience.press\/?p=416380","title":{"rendered":"Canada Summer Daily Low Temperature Trends, 1900-2023"},"content":{"rendered":"\n<figure class=\"wp-block-image size-large\"><img data-recalc-dims=\"1\" loading=\"lazy\" decoding=\"async\" width=\"723\" height=\"591\" data-attachment-id=\"416399\" data-permalink=\"https:\/\/climatescience.press\/?attachment_id=416399\" data-orig-file=\"https:\/\/i0.wp.com\/climatescience.press\/wp-content\/uploads\/2025\/12\/0AQPLqX6NSrUpNd4NZG8zNpbW-ANDphPlOykD8Jls4SykfF2WArofRG5qc3b9qPEIuplFfpbq-6YKP_lVKnLyi0z-hywO1Y3eceMSxDFK43hgBz6pqdiZKXWc9EHTh01j.jpeg?fit=1149%2C939&amp;ssl=1\" data-orig-size=\"1149,939\" data-comments-opened=\"1\" data-image-meta=\"{&quot;aperture&quot;:&quot;0&quot;,&quot;credit&quot;:&quot;&quot;,&quot;camera&quot;:&quot;&quot;,&quot;caption&quot;:&quot;&quot;,&quot;created_timestamp&quot;:&quot;0&quot;,&quot;copyright&quot;:&quot;&quot;,&quot;focal_length&quot;:&quot;0&quot;,&quot;iso&quot;:&quot;0&quot;,&quot;shutter_speed&quot;:&quot;0&quot;,&quot;title&quot;:&quot;&quot;,&quot;orientation&quot;:&quot;0&quot;}\" data-image-title=\"0AQPLqX6NSrUpNd4NZG8zNpbW-ANDphPlOykD8Jls4SykfF2WArofRG5qc3b9qPEIuplFfpbq-6YKP_lVKnLyi0z-hywO1Y3eceMSxDFK43hgBz6pqdiZKXWc9EHTh01j\" data-image-description=\"\" data-image-caption=\"\" data-large-file=\"https:\/\/i0.wp.com\/climatescience.press\/wp-content\/uploads\/2025\/12\/0AQPLqX6NSrUpNd4NZG8zNpbW-ANDphPlOykD8Jls4SykfF2WArofRG5qc3b9qPEIuplFfpbq-6YKP_lVKnLyi0z-hywO1Y3eceMSxDFK43hgBz6pqdiZKXWc9EHTh01j.jpeg?fit=723%2C591&amp;ssl=1\" src=\"https:\/\/i0.wp.com\/climatescience.press\/wp-content\/uploads\/2025\/12\/0AQPLqX6NSrUpNd4NZG8zNpbW-ANDphPlOykD8Jls4SykfF2WArofRG5qc3b9qPEIuplFfpbq-6YKP_lVKnLyi0z-hywO1Y3eceMSxDFK43hgBz6pqdiZKXWc9EHTh01j.jpeg?resize=723%2C591&#038;ssl=1\" alt=\"Line graph showing Canada summer daily minimum temperature trends from 1900 to 2023 across six provinces. The graph illustrates trends for the warmest three days per month, all summer days, and the coolest three days per month, with respective averages and temperature changes over the years.\" class=\"wp-image-416399\" srcset=\"https:\/\/i0.wp.com\/climatescience.press\/wp-content\/uploads\/2025\/12\/0AQPLqX6NSrUpNd4NZG8zNpbW-ANDphPlOykD8Jls4SykfF2WArofRG5qc3b9qPEIuplFfpbq-6YKP_lVKnLyi0z-hywO1Y3eceMSxDFK43hgBz6pqdiZKXWc9EHTh01j.jpeg?resize=1024%2C837&amp;ssl=1 1024w, https:\/\/i0.wp.com\/climatescience.press\/wp-content\/uploads\/2025\/12\/0AQPLqX6NSrUpNd4NZG8zNpbW-ANDphPlOykD8Jls4SykfF2WArofRG5qc3b9qPEIuplFfpbq-6YKP_lVKnLyi0z-hywO1Y3eceMSxDFK43hgBz6pqdiZKXWc9EHTh01j.jpeg?resize=300%2C245&amp;ssl=1 300w, https:\/\/i0.wp.com\/climatescience.press\/wp-content\/uploads\/2025\/12\/0AQPLqX6NSrUpNd4NZG8zNpbW-ANDphPlOykD8Jls4SykfF2WArofRG5qc3b9qPEIuplFfpbq-6YKP_lVKnLyi0z-hywO1Y3eceMSxDFK43hgBz6pqdiZKXWc9EHTh01j.jpeg?resize=768%2C628&amp;ssl=1 768w, https:\/\/i0.wp.com\/climatescience.press\/wp-content\/uploads\/2025\/12\/0AQPLqX6NSrUpNd4NZG8zNpbW-ANDphPlOykD8Jls4SykfF2WArofRG5qc3b9qPEIuplFfpbq-6YKP_lVKnLyi0z-hywO1Y3eceMSxDFK43hgBz6pqdiZKXWc9EHTh01j.jpeg?resize=640%2C523&amp;ssl=1 640w, https:\/\/i0.wp.com\/climatescience.press\/wp-content\/uploads\/2025\/12\/0AQPLqX6NSrUpNd4NZG8zNpbW-ANDphPlOykD8Jls4SykfF2WArofRG5qc3b9qPEIuplFfpbq-6YKP_lVKnLyi0z-hywO1Y3eceMSxDFK43hgBz6pqdiZKXWc9EHTh01j.jpeg?w=1149&amp;ssl=1 1149w\" sizes=\"auto, (max-width: 723px) 100vw, 723px\" \/><\/figure>\n\n\n\n<p class=\"wp-block-paragraph\"><\/p>\n\n\n\n<p class=\"wp-block-paragraph\">From <a href=\"https:\/\/www.drroyspencer.com\/2025\/12\/canada-summer-daily-low-temperature-trends-1900-2023\/\">Roy Spencer, PhD<\/a><\/p>\n\n\n\n<p class=\"wp-block-paragraph\"><small>December 5th, 2025 by Roy W. Spencer, Ph. D.<\/small><\/p>\n\n\n\n<p class=\"wp-block-paragraph\"><em><strong>NOTE<\/strong>: This is the Tmin (daily minimum temperature) version of the Canada temperature trend results I\u00a0<a href=\"https:\/\/www.drroyspencer.com\/2025\/12\/canada-summer-daily-high-temperature-trends-1900-2023\/\">posted yesterday<\/a>, which were for Tmax (daily maximum temperatures). These results are quite different: whereas the high temperatures have seen essentially no warming trends across southern Canada since 1900, the nighttime temperatures have warmed in each one of the 6 provinces. In the next few days, I will post just how much these observed Canadian temperature trends depart from the CMIP6 climate model simulations, which are the primary tool being used to change energy policy.<\/em><\/p>\n\n\n\n<p class=\"wp-block-paragraph\"><strong>SUMMARY<\/strong><\/p>\n\n\n\n<ol class=\"wp-block-list\">\n<li>Over the period 1900-2023, the average summer (JJA) daily low temperatures across the six southernmost large provinces of Canada (British Columbia, Alberta, Saskatchewan, Manitoba, Ontario, and Quebec) show warming trends, averaging +0.14 C\/decade.<\/li>\n\n\n\n<li>The strongest warming (+0.18 C\/decade) occurred for the coolest summer nights (coolest 3 days per summer month), while the warmest summer nights warmed at +0.10 C\/decade.<\/li>\n\n\n\n<li>Whereas 7 of the 10 warmest summer daytime (high) temperatures occurred in the 1930s, 8 of 10 of the warmest nighttime (low) temperatures have occurred since 2003.<\/li>\n\n\n\n<li>Results for the 6 provinces separately are also presented.<\/li>\n<\/ol>\n\n\n\n<p class=\"wp-block-paragraph\"><strong>Introduction<\/strong><\/p>\n\n\n\n<p class=\"wp-block-paragraph\">Below I present analyses of summertime daily low temperature (Tmin) trends from all available stations in the 6 southernmost large provinces, based upon the daily Global Historical Climate Network (GHCNd) dataset. These are the 6 provinces that border the Lower 48 and contain 86% of Canada\u2019s population. (The results for daily high temperatures [Tmax] were\u00a0<a href=\"https:\/\/www.drroyspencer.com\/2025\/12\/canada-summer-daily-high-temperature-trends-1900-2023\/\">posted yesterday<\/a>.)<\/p>\n\n\n\n<p class=\"wp-block-paragraph\">I simply averaged together the relevant statistics (monthly average Tmin, average of the warmest 3 days\u2019 Tmin in each month, and average of the coolest 3 days\u2019 Tmin in each month) from all available stations. Each station had to have at least 90% of the days in a month reporting data for that month to be included in the analysis.<\/p>\n\n\n\n<p class=\"wp-block-paragraph\">Since stations come and go over the years, and since there are some large terrain elevation variations in western Canada, I performed an elevation correction to these Tmin metrics, in all provinces, using the departure of each year\u2019s station-average elevation from the all-year (1900-2023) station average elevation, using a lapse rate of 6.5 deg. C per km. Corrections for average changes in station-average latitude were not done, which might be necessary in the winter since there are large North-South gradients in air temperature then. Such corrections in the summer would likely be small, but I can revisit that nuance at a later time.<\/p>\n\n\n\n<p class=\"wp-block-paragraph\"><strong>Results<\/strong><\/p>\n\n\n\n<p class=\"wp-block-paragraph\">I\u2019ll start with the 6-province average Tmin temperature time series, along with the total number of stations available in each year. In all plots that follow, I list the linear temperature trends, but plot a 3rd order polynomial fit to the data to help capture any multi-decadal variations not well reflected in simple linear trends. In all provinces the number of stations increases from 1900 to the 1970s, then decreases substantially in recent years.<\/p>\n\n\n\n<p class=\"wp-block-paragraph\">As can be seen in the first plot (averages for all 6 major provinces), there has been an average summertime warming trend of +0.14 C\/decade.<\/p>\n\n\n<div class=\"wp-block-image\">\n<figure class=\"aligncenter size-full\"><img data-recalc-dims=\"1\" loading=\"lazy\" decoding=\"async\" width=\"550\" height=\"917\" data-attachment-id=\"416382\" data-permalink=\"https:\/\/climatescience.press\/?attachment_id=416382\" data-orig-file=\"https:\/\/i0.wp.com\/climatescience.press\/wp-content\/uploads\/2025\/12\/0Canada-Tmin-Tavg-Hi3-Lo3-1900-2023-6-southernmost-provinces-550x917-1.jpg?fit=550%2C917&amp;ssl=1\" data-orig-size=\"550,917\" data-comments-opened=\"1\" data-image-meta=\"{&quot;aperture&quot;:&quot;0&quot;,&quot;credit&quot;:&quot;&quot;,&quot;camera&quot;:&quot;&quot;,&quot;caption&quot;:&quot;&quot;,&quot;created_timestamp&quot;:&quot;0&quot;,&quot;copyright&quot;:&quot;&quot;,&quot;focal_length&quot;:&quot;0&quot;,&quot;iso&quot;:&quot;0&quot;,&quot;shutter_speed&quot;:&quot;0&quot;,&quot;title&quot;:&quot;&quot;,&quot;orientation&quot;:&quot;0&quot;}\" data-image-title=\"0Canada-Tmin-Tavg-Hi3-Lo3-1900-2023-6-southernmost-provinces-550&amp;#215;917\" data-image-description=\"\" data-image-caption=\"\" data-large-file=\"https:\/\/i0.wp.com\/climatescience.press\/wp-content\/uploads\/2025\/12\/0Canada-Tmin-Tavg-Hi3-Lo3-1900-2023-6-southernmost-provinces-550x917-1.jpg?fit=550%2C917&amp;ssl=1\" src=\"https:\/\/i0.wp.com\/climatescience.press\/wp-content\/uploads\/2025\/12\/0Canada-Tmin-Tavg-Hi3-Lo3-1900-2023-6-southernmost-provinces-550x917-1.jpg?resize=550%2C917&#038;ssl=1\" alt=\"Graph showing the number of weather stations in Canada from 1900 to 2023, illustrating a peak in the number of stations during the 1970s, followed by a decline.\" class=\"wp-image-416382\" srcset=\"https:\/\/i0.wp.com\/climatescience.press\/wp-content\/uploads\/2025\/12\/0Canada-Tmin-Tavg-Hi3-Lo3-1900-2023-6-southernmost-provinces-550x917-1.jpg?w=550&amp;ssl=1 550w, https:\/\/i0.wp.com\/climatescience.press\/wp-content\/uploads\/2025\/12\/0Canada-Tmin-Tavg-Hi3-Lo3-1900-2023-6-southernmost-provinces-550x917-1.jpg?resize=180%2C300&amp;ssl=1 180w\" sizes=\"auto, (max-width: 550px) 100vw, 550px\" \/><\/figure>\n<\/div>\n\n\n<p class=\"wp-block-paragraph\">I have also annotated 2021, which experienced the extreme heatwave in late June in western Canada. That event helped to push the warmest 3-day average Tmin metric (red curve) to the highest average temperature of any year since 1900. (Just to be clear, this is the warmest 3 days in each month in *minimum* daily temperature [Tmin]).<\/p>\n\n\n\n<p class=\"wp-block-paragraph\">Notably, 8 of the 10 warmest summers in the all-days average Tmin have occurred since 2003. But, as I will show in the next few days, numbers matter: these warming trends are well below what the CMIP6 climate models produce for the same region of Canada.<\/p>\n\n\n\n<p class=\"wp-block-paragraph\"><strong>Individual Provinces<\/strong><\/p>\n\n\n\n<p class=\"wp-block-paragraph\">The results for the individual provinces follow. I present them without comment; my Canadian friends can peruse the results for their home province if they wish. These are presented from West to East:<\/p>\n\n\n<div class=\"wp-block-image\">\n<figure class=\"aligncenter size-full\"><img data-recalc-dims=\"1\" loading=\"lazy\" decoding=\"async\" width=\"550\" height=\"917\" data-attachment-id=\"416385\" data-permalink=\"https:\/\/climatescience.press\/?attachment_id=416385\" data-orig-file=\"https:\/\/i0.wp.com\/climatescience.press\/wp-content\/uploads\/2025\/12\/image-148.png?fit=550%2C917&amp;ssl=1\" data-orig-size=\"550,917\" data-comments-opened=\"1\" data-image-meta=\"{&quot;aperture&quot;:&quot;0&quot;,&quot;credit&quot;:&quot;&quot;,&quot;camera&quot;:&quot;&quot;,&quot;caption&quot;:&quot;&quot;,&quot;created_timestamp&quot;:&quot;0&quot;,&quot;copyright&quot;:&quot;&quot;,&quot;focal_length&quot;:&quot;0&quot;,&quot;iso&quot;:&quot;0&quot;,&quot;shutter_speed&quot;:&quot;0&quot;,&quot;title&quot;:&quot;&quot;,&quot;orientation&quot;:&quot;0&quot;}\" data-image-title=\"image\" data-image-description=\"\" data-image-caption=\"\" data-large-file=\"https:\/\/i0.wp.com\/climatescience.press\/wp-content\/uploads\/2025\/12\/image-148.png?fit=550%2C917&amp;ssl=1\" src=\"https:\/\/i0.wp.com\/climatescience.press\/wp-content\/uploads\/2025\/12\/image-148.png?resize=550%2C917&#038;ssl=1\" alt=\"Graph showing the number of meteorological stations in British Columbia by year from 1900 to 2023, along with a chart of the province-wide average summer daily minimum temperatures (Tmin) during the same period. The graphs indicate warming trends for the warmest and coolest summer nights.\" class=\"wp-image-416385\" srcset=\"https:\/\/i0.wp.com\/climatescience.press\/wp-content\/uploads\/2025\/12\/image-148.png?w=550&amp;ssl=1 550w, https:\/\/i0.wp.com\/climatescience.press\/wp-content\/uploads\/2025\/12\/image-148.png?resize=180%2C300&amp;ssl=1 180w\" sizes=\"auto, (max-width: 550px) 100vw, 550px\" \/><\/figure>\n<\/div>\n\n<div class=\"wp-block-image\">\n<figure class=\"aligncenter size-full\"><img data-recalc-dims=\"1\" loading=\"lazy\" decoding=\"async\" width=\"550\" height=\"917\" data-attachment-id=\"416388\" data-permalink=\"https:\/\/climatescience.press\/?attachment_id=416388\" data-orig-file=\"https:\/\/i0.wp.com\/climatescience.press\/wp-content\/uploads\/2025\/12\/image-150.png?fit=550%2C917&amp;ssl=1\" data-orig-size=\"550,917\" data-comments-opened=\"1\" data-image-meta=\"{&quot;aperture&quot;:&quot;0&quot;,&quot;credit&quot;:&quot;&quot;,&quot;camera&quot;:&quot;&quot;,&quot;caption&quot;:&quot;&quot;,&quot;created_timestamp&quot;:&quot;0&quot;,&quot;copyright&quot;:&quot;&quot;,&quot;focal_length&quot;:&quot;0&quot;,&quot;iso&quot;:&quot;0&quot;,&quot;shutter_speed&quot;:&quot;0&quot;,&quot;title&quot;:&quot;&quot;,&quot;orientation&quot;:&quot;0&quot;}\" data-image-title=\"image\" data-image-description=\"\" data-image-caption=\"\" data-large-file=\"https:\/\/i0.wp.com\/climatescience.press\/wp-content\/uploads\/2025\/12\/image-150.png?fit=550%2C917&amp;ssl=1\" src=\"https:\/\/i0.wp.com\/climatescience.press\/wp-content\/uploads\/2025\/12\/image-150.png?resize=550%2C917&#038;ssl=1\" alt=\"Graph depicting the number of weather stations in Alberta from 1900 to 2020, showing fluctuations in data collection over the years.\" class=\"wp-image-416388\" srcset=\"https:\/\/i0.wp.com\/climatescience.press\/wp-content\/uploads\/2025\/12\/image-150.png?w=550&amp;ssl=1 550w, https:\/\/i0.wp.com\/climatescience.press\/wp-content\/uploads\/2025\/12\/image-150.png?resize=180%2C300&amp;ssl=1 180w\" sizes=\"auto, (max-width: 550px) 100vw, 550px\" \/><\/figure>\n<\/div>\n\n<div class=\"wp-block-image\">\n<figure class=\"aligncenter size-full\"><img data-recalc-dims=\"1\" loading=\"lazy\" decoding=\"async\" width=\"550\" height=\"917\" data-attachment-id=\"416390\" data-permalink=\"https:\/\/climatescience.press\/?attachment_id=416390\" data-orig-file=\"https:\/\/i0.wp.com\/climatescience.press\/wp-content\/uploads\/2025\/12\/image-152.png?fit=550%2C917&amp;ssl=1\" data-orig-size=\"550,917\" data-comments-opened=\"1\" data-image-meta=\"{&quot;aperture&quot;:&quot;0&quot;,&quot;credit&quot;:&quot;&quot;,&quot;camera&quot;:&quot;&quot;,&quot;caption&quot;:&quot;&quot;,&quot;created_timestamp&quot;:&quot;0&quot;,&quot;copyright&quot;:&quot;&quot;,&quot;focal_length&quot;:&quot;0&quot;,&quot;iso&quot;:&quot;0&quot;,&quot;shutter_speed&quot;:&quot;0&quot;,&quot;title&quot;:&quot;&quot;,&quot;orientation&quot;:&quot;0&quot;}\" data-image-title=\"image\" data-image-description=\"\" data-image-caption=\"\" data-large-file=\"https:\/\/i0.wp.com\/climatescience.press\/wp-content\/uploads\/2025\/12\/image-152.png?fit=550%2C917&amp;ssl=1\" src=\"https:\/\/i0.wp.com\/climatescience.press\/wp-content\/uploads\/2025\/12\/image-152.png?resize=550%2C917&#038;ssl=1\" alt=\"Line graph showing the number of weather stations in Saskatchewan from 1900 to 2020, with fluctuations over the years.\" class=\"wp-image-416390\" srcset=\"https:\/\/i0.wp.com\/climatescience.press\/wp-content\/uploads\/2025\/12\/image-152.png?w=550&amp;ssl=1 550w, https:\/\/i0.wp.com\/climatescience.press\/wp-content\/uploads\/2025\/12\/image-152.png?resize=180%2C300&amp;ssl=1 180w\" sizes=\"auto, (max-width: 550px) 100vw, 550px\" \/><\/figure>\n<\/div>\n\n<div class=\"wp-block-image\">\n<figure class=\"aligncenter size-full\"><img data-recalc-dims=\"1\" loading=\"lazy\" decoding=\"async\" width=\"550\" height=\"917\" data-attachment-id=\"416392\" data-permalink=\"https:\/\/climatescience.press\/?attachment_id=416392\" data-orig-file=\"https:\/\/i0.wp.com\/climatescience.press\/wp-content\/uploads\/2025\/12\/image-154.png?fit=550%2C917&amp;ssl=1\" data-orig-size=\"550,917\" data-comments-opened=\"1\" data-image-meta=\"{&quot;aperture&quot;:&quot;0&quot;,&quot;credit&quot;:&quot;&quot;,&quot;camera&quot;:&quot;&quot;,&quot;caption&quot;:&quot;&quot;,&quot;created_timestamp&quot;:&quot;0&quot;,&quot;copyright&quot;:&quot;&quot;,&quot;focal_length&quot;:&quot;0&quot;,&quot;iso&quot;:&quot;0&quot;,&quot;shutter_speed&quot;:&quot;0&quot;,&quot;title&quot;:&quot;&quot;,&quot;orientation&quot;:&quot;0&quot;}\" data-image-title=\"image\" data-image-description=\"\" data-image-caption=\"\" data-large-file=\"https:\/\/i0.wp.com\/climatescience.press\/wp-content\/uploads\/2025\/12\/image-154.png?fit=550%2C917&amp;ssl=1\" src=\"https:\/\/i0.wp.com\/climatescience.press\/wp-content\/uploads\/2025\/12\/image-154.png?resize=550%2C917&#038;ssl=1\" alt=\"Line graph showing the number of weather stations in Manitoba from 1900 to 2020, indicating fluctuations over the years.\" class=\"wp-image-416392\" srcset=\"https:\/\/i0.wp.com\/climatescience.press\/wp-content\/uploads\/2025\/12\/image-154.png?w=550&amp;ssl=1 550w, https:\/\/i0.wp.com\/climatescience.press\/wp-content\/uploads\/2025\/12\/image-154.png?resize=180%2C300&amp;ssl=1 180w\" sizes=\"auto, (max-width: 550px) 100vw, 550px\" \/><\/figure>\n<\/div>\n\n<div class=\"wp-block-image\">\n<figure class=\"aligncenter size-full\"><img data-recalc-dims=\"1\" loading=\"lazy\" decoding=\"async\" width=\"550\" height=\"917\" data-attachment-id=\"416394\" data-permalink=\"https:\/\/climatescience.press\/?attachment_id=416394\" data-orig-file=\"https:\/\/i0.wp.com\/climatescience.press\/wp-content\/uploads\/2025\/12\/image-156.png?fit=550%2C917&amp;ssl=1\" data-orig-size=\"550,917\" data-comments-opened=\"1\" data-image-meta=\"{&quot;aperture&quot;:&quot;0&quot;,&quot;credit&quot;:&quot;&quot;,&quot;camera&quot;:&quot;&quot;,&quot;caption&quot;:&quot;&quot;,&quot;created_timestamp&quot;:&quot;0&quot;,&quot;copyright&quot;:&quot;&quot;,&quot;focal_length&quot;:&quot;0&quot;,&quot;iso&quot;:&quot;0&quot;,&quot;shutter_speed&quot;:&quot;0&quot;,&quot;title&quot;:&quot;&quot;,&quot;orientation&quot;:&quot;0&quot;}\" data-image-title=\"image\" data-image-description=\"\" data-image-caption=\"\" data-large-file=\"https:\/\/i0.wp.com\/climatescience.press\/wp-content\/uploads\/2025\/12\/image-156.png?fit=550%2C917&amp;ssl=1\" src=\"https:\/\/i0.wp.com\/climatescience.press\/wp-content\/uploads\/2025\/12\/image-156.png?resize=550%2C917&#038;ssl=1\" alt=\"Graph showing the number of weather stations in Ontario by year from 1900 to 2023 and temperature trends for summer average Tmin, highlighting the warmest and coolest days.\" class=\"wp-image-416394\" srcset=\"https:\/\/i0.wp.com\/climatescience.press\/wp-content\/uploads\/2025\/12\/image-156.png?w=550&amp;ssl=1 550w, https:\/\/i0.wp.com\/climatescience.press\/wp-content\/uploads\/2025\/12\/image-156.png?resize=180%2C300&amp;ssl=1 180w\" sizes=\"auto, (max-width: 550px) 100vw, 550px\" \/><\/figure>\n<\/div>\n\n<div class=\"wp-block-image\">\n<figure class=\"aligncenter size-full\"><img data-recalc-dims=\"1\" loading=\"lazy\" decoding=\"async\" width=\"550\" height=\"917\" data-attachment-id=\"416397\" data-permalink=\"https:\/\/climatescience.press\/?attachment_id=416397\" data-orig-file=\"https:\/\/i0.wp.com\/climatescience.press\/wp-content\/uploads\/2025\/12\/image-158.png?fit=550%2C917&amp;ssl=1\" data-orig-size=\"550,917\" data-comments-opened=\"1\" data-image-meta=\"{&quot;aperture&quot;:&quot;0&quot;,&quot;credit&quot;:&quot;&quot;,&quot;camera&quot;:&quot;&quot;,&quot;caption&quot;:&quot;&quot;,&quot;created_timestamp&quot;:&quot;0&quot;,&quot;copyright&quot;:&quot;&quot;,&quot;focal_length&quot;:&quot;0&quot;,&quot;iso&quot;:&quot;0&quot;,&quot;shutter_speed&quot;:&quot;0&quot;,&quot;title&quot;:&quot;&quot;,&quot;orientation&quot;:&quot;0&quot;}\" data-image-title=\"image\" data-image-description=\"\" data-image-caption=\"\" data-large-file=\"https:\/\/i0.wp.com\/climatescience.press\/wp-content\/uploads\/2025\/12\/image-158.png?fit=550%2C917&amp;ssl=1\" src=\"https:\/\/i0.wp.com\/climatescience.press\/wp-content\/uploads\/2025\/12\/image-158.png?resize=550%2C917&#038;ssl=1\" alt=\"Graph showing the number of weather stations in Quebec by year from 1900 to 2020, with a peak in the 1960s.\" class=\"wp-image-416397\" srcset=\"https:\/\/i0.wp.com\/climatescience.press\/wp-content\/uploads\/2025\/12\/image-158.png?w=550&amp;ssl=1 550w, https:\/\/i0.wp.com\/climatescience.press\/wp-content\/uploads\/2025\/12\/image-158.png?resize=180%2C300&amp;ssl=1 180w\" sizes=\"auto, (max-width: 550px) 100vw, 550px\" \/><\/figure>\n<\/div>\n\n\n<p class=\"wp-block-paragraph\"><\/p>\n","protected":false},"excerpt":{"rendered":"<p>This is the Tmin (daily minimum temperature) version of the Canada temperature trend results I posted yesterday, which were for Tmax (daily maximum temperatures). These results are quite different: whereas the high temperatures have seen essentially no warming trends across southern Canada since 1900, the nighttime temperatures have warmed in each one of the 6 provinces. In the next few days I will post just how much these observed Canadian temperature trends depart from the CMIP6 climate model simulations, which are the primary tool being used to change energy policy.<\/p>\n","protected":false},"author":121246920,"featured_media":416399,"comment_status":"open","ping_status":"open","sticky":false,"template":"","format":"standard","meta":{"_coblocks_attr":"","_coblocks_dimensions":"","_coblocks_responsive_height":"","_coblocks_accordion_ie_support":"","_crdt_document":"","advanced_seo_description":"","jetpack_seo_html_title":"","jetpack_seo_noindex":false,"_jetpack_newsletter_access":"","_jetpack_dont_email_post_to_subs":false,"_jetpack_newsletter_tier_id":0,"_jetpack_memberships_contains_paywalled_content":false,"_jetpack_memberships_contains_paid_content":false,"footnotes":"","jetpack_publicize_message":"","jetpack_publicize_feature_enabled":true,"jetpack_social_post_already_shared":false,"jetpack_social_options":{"image_generator_settings":{"template":"highway","default_image_id":0,"font":"","enabled":true,"token":"eyJpbWciOiJodHRwczpcL1wvaTAud3AuY29tXC9jbGltYXRlLXNjaWVuY2UucHJlc3NcL3dwLWNvbnRlbnRcL3VwbG9hZHNcLzIwMjVcLzEyXC8wQVFQTHFYNk5TclVwTmQ0TlpHOHpOcGJXLUFORHBoUGxPeWtEOEpsczRTeWtmRjJXQXJvZlJHNXFjM2I5cVBFSXVwbEZmcGJxLTZZS1BfbFZLbkx5aTB6LWh5d08xWTNlY2VNU3hERks0M2hnQno2cHFkaVpLWFdjOUVIVGgwMWouanBlZz9maXQ9NzIzJTJDNTkxJnNzbD0xIiwidHh0IjoiQ2FuYWRhIFN1bW1lciBEYWlseSBMb3cgVGVtcGVyYXR1cmUgVHJlbmRzLCAxOTAwLTIwMjMiLCJ0ZW1wbGF0ZSI6ImhpZ2h3YXkiLCJmb250IjoiIiwiYmxvZ19pZCI6MTU1ODEyNDQ5fQ.IoEJj4F3Mgf_oU9GYfVgMFToFcFb8y53oy_ZPKzWKM8MQ"},"version":2},"jetpack_post_was_ever_published":false},"categories":[1],"tags":[691840029,691820083,691839993,691840030,691840028,691840027],"class_list":{"0":"post-416380","1":"post","2":"type-post","3":"status-publish","4":"format-standard","5":"has-post-thumbnail","6":"hentry","7":"category-uncategorized","8":"tag-6-provinces","9":"tag-canada","10":"tag-global-historical-climate-network-ghcnd-dataset","11":"tag-period-1900-2023","12":"tag-tmax-daily-maximum-temperatures","13":"tag-tmin-daily-minimum-temperature","15":"fallback-thumbnail"},"jetpack_publicize_connections":[],"jetpack_featured_media_url":"https:\/\/i0.wp.com\/climatescience.press\/wp-content\/uploads\/2025\/12\/0AQPLqX6NSrUpNd4NZG8zNpbW-ANDphPlOykD8Jls4SykfF2WArofRG5qc3b9qPEIuplFfpbq-6YKP_lVKnLyi0z-hywO1Y3eceMSxDFK43hgBz6pqdiZKXWc9EHTh01j.jpeg?fit=1149%2C939&ssl=1","jetpack_likes_enabled":true,"jetpack_sharing_enabled":true,"jetpack_shortlink":"https:\/\/wp.me\/paxLW1-1KjO","jetpack-related-posts":[{"id":416804,"url":"https:\/\/climatescience.press\/?p=416804","url_meta":{"origin":416380,"position":0},"title":"Canada Summer Temperature Trends, 1900-2023: Part Deux","author":"uwe.roland.gross","date":"10\/12\/2025","format":false,"excerpt":"The following figure shows the daily high (Tmax) and low (Tmin) summer (June-July-August) temperature trends, 1900-2023, for the 6 provinces from which I analyzed data. The other provinces have very few stations by comparison to these six.","rel":"","context":"In \"Canada\"","block_context":{"text":"Canada","link":"https:\/\/climatescience.press\/?tag=canada"},"img":{"alt_text":"","src":"https:\/\/i0.wp.com\/climatescience.press\/wp-content\/uploads\/2025\/12\/0Canada-map-revised-Tmax-Tmin-trends-scaled-1.jpg?fit=1200%2C831&ssl=1&resize=350%2C200","width":350,"height":200,"srcset":"https:\/\/i0.wp.com\/climatescience.press\/wp-content\/uploads\/2025\/12\/0Canada-map-revised-Tmax-Tmin-trends-scaled-1.jpg?fit=1200%2C831&ssl=1&resize=350%2C200 1x, https:\/\/i0.wp.com\/climatescience.press\/wp-content\/uploads\/2025\/12\/0Canada-map-revised-Tmax-Tmin-trends-scaled-1.jpg?fit=1200%2C831&ssl=1&resize=525%2C300 1.5x, https:\/\/i0.wp.com\/climatescience.press\/wp-content\/uploads\/2025\/12\/0Canada-map-revised-Tmax-Tmin-trends-scaled-1.jpg?fit=1200%2C831&ssl=1&resize=700%2C400 2x, https:\/\/i0.wp.com\/climatescience.press\/wp-content\/uploads\/2025\/12\/0Canada-map-revised-Tmax-Tmin-trends-scaled-1.jpg?fit=1200%2C831&ssl=1&resize=1050%2C600 3x"},"classes":[]},{"id":416006,"url":"https:\/\/climatescience.press\/?p=416006","url_meta":{"origin":416380,"position":1},"title":"Canada Summer Daily High Temperature Trends, 1900-2023","author":"uwe.roland.gross","date":"04\/12\/2025","format":false,"excerpt":"Given media reports, it is likely that most Canadians think they have been experiencing unprecedented summer warmth in the last couple of decades. But this isn\u2019t true.","rel":"","context":"In \"extreme heatwave\"","block_context":{"text":"extreme heatwave","link":"https:\/\/climatescience.press\/?tag=extreme-heatwave"},"img":{"alt_text":"","src":"https:\/\/i0.wp.com\/climatescience.press\/wp-content\/uploads\/2025\/12\/0AQNQGwrwtEn_Y_DleGLB7YbKMO7qPYJAAXaCkDkbTWd4wN0jUuOuBZya5g0-xOXDHFjNolHWs45V22ppa_ICoEDzKUtthC5eFlGsJhM7e3KoWeLIJ_XwhNI0a-11tQ-q-1.jpeg?fit=1200%2C793&ssl=1&resize=350%2C200","width":350,"height":200,"srcset":"https:\/\/i0.wp.com\/climatescience.press\/wp-content\/uploads\/2025\/12\/0AQNQGwrwtEn_Y_DleGLB7YbKMO7qPYJAAXaCkDkbTWd4wN0jUuOuBZya5g0-xOXDHFjNolHWs45V22ppa_ICoEDzKUtthC5eFlGsJhM7e3KoWeLIJ_XwhNI0a-11tQ-q-1.jpeg?fit=1200%2C793&ssl=1&resize=350%2C200 1x, https:\/\/i0.wp.com\/climatescience.press\/wp-content\/uploads\/2025\/12\/0AQNQGwrwtEn_Y_DleGLB7YbKMO7qPYJAAXaCkDkbTWd4wN0jUuOuBZya5g0-xOXDHFjNolHWs45V22ppa_ICoEDzKUtthC5eFlGsJhM7e3KoWeLIJ_XwhNI0a-11tQ-q-1.jpeg?fit=1200%2C793&ssl=1&resize=525%2C300 1.5x, https:\/\/i0.wp.com\/climatescience.press\/wp-content\/uploads\/2025\/12\/0AQNQGwrwtEn_Y_DleGLB7YbKMO7qPYJAAXaCkDkbTWd4wN0jUuOuBZya5g0-xOXDHFjNolHWs45V22ppa_ICoEDzKUtthC5eFlGsJhM7e3KoWeLIJ_XwhNI0a-11tQ-q-1.jpeg?fit=1200%2C793&ssl=1&resize=700%2C400 2x, https:\/\/i0.wp.com\/climatescience.press\/wp-content\/uploads\/2025\/12\/0AQNQGwrwtEn_Y_DleGLB7YbKMO7qPYJAAXaCkDkbTWd4wN0jUuOuBZya5g0-xOXDHFjNolHWs45V22ppa_ICoEDzKUtthC5eFlGsJhM7e3KoWeLIJ_XwhNI0a-11tQ-q-1.jpeg?fit=1200%2C793&ssl=1&resize=1050%2C600 3x"},"classes":[]},{"id":345437,"url":"https:\/\/climatescience.press\/?p=345437","url_meta":{"origin":416380,"position":2},"title":"NOAA\u2019s U.S. Temperature Data Demonstrate that Population Growth UHIs &amp; Measurement Inadequacies Drive Tavg Increasing Outcomes \u2013 Not Climate Change","author":"uwe.roland.gross","date":"04\/10\/2024","format":false,"excerpt":"NOAA\u2019s U.S. contiguous U.S. summer (June through August) measured minimum and maximum temperatures trends over the period 1895 through 2024 (shown below from NOAA\u2019s Climate at a Glance Times series data website) show clear and distinct differing temperature trend increasing growth compared to the calculated average temperature trend outcome.","rel":"","context":"In \"NOAA\"","block_context":{"text":"NOAA","link":"https:\/\/climatescience.press\/?tag=noaa"},"img":{"alt_text":"","src":"https:\/\/i0.wp.com\/climatescience.press\/wp-content\/uploads\/2024\/10\/0Urban-Heat-Island-Effect-A162104504.jpg?fit=1200%2C638&ssl=1&resize=350%2C200","width":350,"height":200,"srcset":"https:\/\/i0.wp.com\/climatescience.press\/wp-content\/uploads\/2024\/10\/0Urban-Heat-Island-Effect-A162104504.jpg?fit=1200%2C638&ssl=1&resize=350%2C200 1x, https:\/\/i0.wp.com\/climatescience.press\/wp-content\/uploads\/2024\/10\/0Urban-Heat-Island-Effect-A162104504.jpg?fit=1200%2C638&ssl=1&resize=525%2C300 1.5x, https:\/\/i0.wp.com\/climatescience.press\/wp-content\/uploads\/2024\/10\/0Urban-Heat-Island-Effect-A162104504.jpg?fit=1200%2C638&ssl=1&resize=700%2C400 2x, https:\/\/i0.wp.com\/climatescience.press\/wp-content\/uploads\/2024\/10\/0Urban-Heat-Island-Effect-A162104504.jpg?fit=1200%2C638&ssl=1&resize=1050%2C600 3x"},"classes":[]},{"id":399560,"url":"https:\/\/climatescience.press\/?p=399560","url_meta":{"origin":416380,"position":3},"title":"The Hottest Summer Days in D.C. Have Not Gotten Hotter in Last 40 Years","author":"uwe.roland.gross","date":"02\/09\/2025","format":false,"excerpt":"\u2026but the coolest summer nights have warmed by 5 deg. F.","rel":"","context":"In \"D.C. Urban Warming Trends\"","block_context":{"text":"D.C. 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They are especially guilty of hyping supposed \u201chottest\u201d days, months, years, or decades.","rel":"","context":"In \"Climate change\"","block_context":{"text":"Climate change","link":"https:\/\/climatescience.press\/?tag=climate-change"},"img":{"alt_text":"","src":"https:\/\/i0.wp.com\/climatescience.press\/wp-content\/uploads\/2024\/10\/00Screenshot-2024-10-08-074903.png?fit=1200%2C600&ssl=1&resize=350%2C200","width":350,"height":200,"srcset":"https:\/\/i0.wp.com\/climatescience.press\/wp-content\/uploads\/2024\/10\/00Screenshot-2024-10-08-074903.png?fit=1200%2C600&ssl=1&resize=350%2C200 1x, https:\/\/i0.wp.com\/climatescience.press\/wp-content\/uploads\/2024\/10\/00Screenshot-2024-10-08-074903.png?fit=1200%2C600&ssl=1&resize=525%2C300 1.5x, https:\/\/i0.wp.com\/climatescience.press\/wp-content\/uploads\/2024\/10\/00Screenshot-2024-10-08-074903.png?fit=1200%2C600&ssl=1&resize=700%2C400 2x, https:\/\/i0.wp.com\/climatescience.press\/wp-content\/uploads\/2024\/10\/00Screenshot-2024-10-08-074903.png?fit=1200%2C600&ssl=1&resize=1050%2C600 3x"},"classes":[]},{"id":255147,"url":"https:\/\/climatescience.press\/?p=255147","url_meta":{"origin":416380,"position":5},"title":"Urbanization Effects on GHCN Temperature Trends, Part IV: UHI Effects on Tmax and Tmin","author":"uwe.roland.gross","date":"28\/04\/2023","format":false,"excerpt":"This is part 4 of my series on quantifying Urban Heat Island (UHI) effects on surface air temperatures as reported in the monthly GHCN datasets produced by NOAA.","rel":"","context":"In \"GHCN temperature trends\"","block_context":{"text":"GHCN temperature trends","link":"https:\/\/climatescience.press\/?tag=ghcn-temperature-trends"},"img":{"alt_text":"","src":"https:\/\/i0.wp.com\/climatescience.press\/wp-content\/uploads\/2023\/04\/00UHI-May-June-July-Tmax-Tmin-2.jpg?fit=864%2C960&ssl=1&resize=350%2C200","width":350,"height":200,"srcset":"https:\/\/i0.wp.com\/climatescience.press\/wp-content\/uploads\/2023\/04\/00UHI-May-June-July-Tmax-Tmin-2.jpg?fit=864%2C960&ssl=1&resize=350%2C200 1x, https:\/\/i0.wp.com\/climatescience.press\/wp-content\/uploads\/2023\/04\/00UHI-May-June-July-Tmax-Tmin-2.jpg?fit=864%2C960&ssl=1&resize=525%2C300 1.5x, https:\/\/i0.wp.com\/climatescience.press\/wp-content\/uploads\/2023\/04\/00UHI-May-June-July-Tmax-Tmin-2.jpg?fit=864%2C960&ssl=1&resize=700%2C400 2x"},"classes":[]}],"_links":{"self":[{"href":"https:\/\/climatescience.press\/index.php?rest_route=\/wp\/v2\/posts\/416380","targetHints":{"allow":["GET"]}}],"collection":[{"href":"https:\/\/climatescience.press\/index.php?rest_route=\/wp\/v2\/posts"}],"about":[{"href":"https:\/\/climatescience.press\/index.php?rest_route=\/wp\/v2\/types\/post"}],"author":[{"embeddable":true,"href":"https:\/\/climatescience.press\/index.php?rest_route=\/wp\/v2\/users\/121246920"}],"replies":[{"embeddable":true,"href":"https:\/\/climatescience.press\/index.php?rest_route=%2Fwp%2Fv2%2Fcomments&post=416380"}],"version-history":[{"count":8,"href":"https:\/\/climatescience.press\/index.php?rest_route=\/wp\/v2\/posts\/416380\/revisions"}],"predecessor-version":[{"id":416402,"href":"https:\/\/climatescience.press\/index.php?rest_route=\/wp\/v2\/posts\/416380\/revisions\/416402"}],"wp:featuredmedia":[{"embeddable":true,"href":"https:\/\/climatescience.press\/index.php?rest_route=\/wp\/v2\/media\/416399"}],"wp:attachment":[{"href":"https:\/\/climatescience.press\/index.php?rest_route=%2Fwp%2Fv2%2Fmedia&parent=416380"}],"wp:term":[{"taxonomy":"category","embeddable":true,"href":"https:\/\/climatescience.press\/index.php?rest_route=%2Fwp%2Fv2%2Fcategories&post=416380"},{"taxonomy":"post_tag","embeddable":true,"href":"https:\/\/climatescience.press\/index.php?rest_route=%2Fwp%2Fv2%2Ftags&post=416380"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}