The year 1540 stands out as an extreme European megadrought and heat event—often described as a “worst-case” or among the most severe in the past 500 years. Scientific studies (notably based on hundreds of contemporary chronicles and documentary sources covering large parts of western and central Europe) reconstruct an approximately 11-month period of exceptional dryness and heat, with precipitation in many areas far below modern instrumental minima (sometimes estimated at roughly a third or less of typical amounts in places).

Rivers ran extremely low (the Rhine reduced dramatically; Lake Constance levels dropped so far that islands connected to the mainland in some reports), soils cracked, wildfires and settlement fires surged, livestock died of thirst/heat, and water shortages were widespread. Temperatures were reconstructed as unusually high for the period, with soil desiccation likely amplifying the heat via feedbacks. Contemporary accounts describe conditions that felt apocalyptic to people at the time.

This 1540 peak occurred within a broader dry phase. Research on central European drought indices and documentary records identifies the summers of 1531–1540 as among the driest (or the driest) summer decades of the past five centuries in regions such as the Czech Lands, with dry conditions of varying intensity in multiple years including 1532, 1534–1536, 1538, and especially 1540. The summers of 1534 and 1535 are specifically noted in analyses as nearly as disastrously dry in places, contributing to crop stress, water shortages, and related hardships (including reports of caterpillar plagues and localized famine conditions in some areas). The decade as a whole featured repeated dry spells that compounded agricultural and hydrological stress across much of the continent, even if not every year matched 1540’s intensity.

These events took place amid the broader Little Ice Age, a period of generally cooler and more variable conditions in Europe, which makes the anomalous warmth and dryness of 1540 (and parts of the surrounding decade) particularly striking. Climate models have difficulty fully reproducing an event of 1540’s severity from the available long-term data.

Impacts included severe crop failures or reduced yields in affected areas, water scarcity, elevated disease risk (e.g., from contaminated remaining water sources), and social strain, though the overall societal crisis did not spiral in exactly the same way as some colder/wetter famine years of the era. Modern comparisons (such as to 21st-century European droughts) often reference 1540 as a historical benchmark for severity.

Sources for these reconstructions include multi-author papers in journals such as Climatic Change (e.g., the 2014 “worst case” analysis of 1540) and Climate of the Past studies on the 1531–1540 decade, along with syntheses drawing on hundreds of primary chronicles.

1540 documentary evidence

The 1540 European megadrought and heat event is one of the best-documented pre-instrumental climate extremes in European history, reconstructed primarily from contemporary written sources rather than solely from proxies like tree rings.

The foundational analysis (Wetter, Pfister et al., 2014, in Climatic Change) draws on more than 300 first-hand documentary weather reports from an area of roughly 2–3 million km². These cover Austria, Belgium, the Czech Republic, England, France, Germany, Hungary, Italy, the Netherlands, Poland, Portugal, Romania, Russia, Slovakia, Spain, Sweden, and Switzerland (with the densest coverage in eastern France, Switzerland, southern Germany, the Czech Lands, and northern Italy). Wikipedia and related summaries often refer to over 220 chronicles describing impacts in detail.

Types of evidence include:

• Narrative chronicles, annals, and personal diaries/memoirs (often by town scribes, clergy, mayors, or vine-growers).
• Weather diaries with day-by-day notes on precipitation, temperature sensations, and phenology.
• Official records (letters, administrative accounts, measures against water shortages or fires).
• Religious documents (rogation/prayer ceremonies for rain, especially noted in Spain and Italy).
• Economic and agricultural notes (harvest timing, prices, mill operations, livestock losses).
• Observations of environmental impacts (river/lake levels, soil cracks, fires, fish kills, vegetation stress).

These are qualitative or semi-quantitative (e.g., counts of rain days or descriptions of intensity) and were cross-checked for consistency across regions.

Hans Stolz (or Stoltz), vine-grower and mayor of Guebwiller (Alsace, modern France):

One of the most continuous and detailed chroniclers. His entry for 1540 (Julian calendar) notes a moderately cold January, then warm and dry February; three rainy days in early March followed by ice in mornings but warm days; completely dry April and May (no rain or snow); mostly dry June with some light rain at the end; and “terribly hot and dry” July through early August, making water scarce and expensive. Similar dry, warm conditions continued into autumn and early winter with little frost or snow. This is frequently quoted as representative of western/central European conditions.

Marcin Biem (theologian and rector of Kraków University, Poland):

The only known detailed weather diary from the period in Europe. His daily records allowed statistical reconstruction of precipitation frequency for Kraków, showing values comparable to the Swiss Plateau estimates (far below 20th-century norms).

Swiss Plateau chroniclers (e.g., Heinrich Bullinger in Zürich, Fridolin Ryff and Adelberg Meyer in Basel, Hans Salat):

Bullinger reported that it never rained for a full day or night between February and late September. Others counted only a handful of short, weak rain spells across long periods. Digging >1.5 m into the dried bed of the Suhre river (Lucerne area) yielded no water.

Northern Italy:

Chronicles describe the winter of 1539–40 as “like July,” with no rain for nearly 200 consecutive days in some accounts (from autumn 1539 into spring 1540). The drought then spread northward.

Other regional notes:

In England, little or no rain from roughly mid-July to mid-October. In Bohemia (e.g., Louny), rain was extremely rare over multi-month stretches. Low river flows allowed people to wade or ride across the Rhine, Elbe, Seine, and others; Lake Constance dropped so low that Roman coins (including finds by people like Anna Schmid) were exposed, and Lindau temporarily connected to the mainland. Widespread reports of soil cracking, forest/settlement fires (dozens of town fires in German lands alone, including the destructive Einbeck fire), fish kills, and secondary blossoming of trees/vines in autumn.

Rogation ceremonies for rain appear in Spanish and Italian records starting as early as late 1539 in some places.

Researchers quantified precipitation days (NPD) and estimated amounts for core regions (Swiss Plateau and Kraków), finding them significantly below the lowest values in the modern instrumental record for spring–autumn. Phenological data (e.g., extremely early vine flowering, grape ripening, cherry blossoming, and even second flowering) supported temperature reconstructions indicating exceptionally high spring–summer values, with possible maxima above 40°C in places due to soil desiccation feedback. Independent corroboration came from hydrological observations and the surge in fires.

There has been some debate (e.g., with tree-ring specialists), as dendrochronological signals do not always capture the full intensity of short, extreme events in the same way, but the multi-source documentary consistency across a large area remains strong. The 1540 event is often framed as a “Black Swan” or worst-case analogue for understanding extreme heat-drought risks.

Primary access points for deeper exploration include the 2014 Wetter et al. paper and its supplementary tables, Pfister’s related works (including the “Black Swan of 1540” chapter), country-specific climate history compilations (e.g., for the Czech Lands or Switzerland), and the Wikipedia synthesis that aggregates many of these details with maps of source locations. Many original chronicles are held in regional archives or have been edited/published in historical series.

Hans Stolz weather diary

Hans Stolz (also spelled Stoltz; c. 1475 – after 1546), a vine-grower (winzer), burgher, and local official in Guebwiller (German: Gebweiler) in Alsace (then part of the Holy Roman Empire, under the Prince-Abbey of Murbach), authored one of the most valuable continuous local chronicles from the early 16th century.

His work is commonly known as the Ursprung und Anfang der Statt Gebweyler (“Origin and Beginning of the Town of Guebwiller”) or simply the Gebweiler/Guebwiller Chronicle (or Tagebuch/diary in some references).

It is not a pure daily weather diary like some astronomical or scholarly records of the era, but a town chronicle that interweaves local history, legends, daily life observations, economic notes, and detailed weather comments—especially valuable for the period around the Peasants’ War (1520s) and into the early 1540s.

Climate historians (notably Christian Pfister and colleagues) frequently cite his 1540 entries as a high-quality, continuous first-hand source for the western/central European megadrought.

Background and Manuscript

Stolz appears in local tax rolls (Gewerff) in the 1520s and 1546. He held roles such as in the vine-growers’ guild of the upper town and a boundary commission, indicating middle-to-upper burgher status with administrative ties to the abbey.

The original is lost. The main surviving version is a 1620 copy (57 folios) by Nicolas Talloutsche of Lure, held at the Bibliothèque municipale de Colmar (Ms 539). Local tradition sometimes called it the “Chronique du cordonnier” (shoemaker’s chronicle), though Stolz was a vine-grower.

It mixes mythical/historical origins of the town with contemporary events. The language shows Alsatian/Which (Romance-influenced) traits in orthography.

Published editions:

• Julien Sée (1871): Hans Stoltz’s Ursprung und Anfang der Statt Gebweyler. Sagen und Tagebuch eines Bürgers von Gebweiler zur Zeit des Bauernkrieges (in the “Chroniques d’Alsace” series, Colmar).
• Wolfram Stolz (1979): Die Hans Stolz’sche Gebweiler Chronik. Zeugenbericht über den Bauernkrieg am Oberrhein (Freiburg; includes transcription, facsimiles, and commentary; the 1540 weather excerpt is on p. 373). Note: Some local historians caution that the 1979 edition’s preface and transcriptions can be approximate or somewhat journalistic.

It later informed the 18th-century Chronique des Dominicains de Guebwiller by Séraphin Dietler.

The 1540 Weather Entry

The most-cited passage (Julian calendar dates; transcription after Wolfram Stolz) describes the progressive drought and heat with practical economic notes:

“Ano 1540. Als diß jar der jenner zirnblich kalt war, da fieng der hornung an warm und und truckhen durchauß, der mertz fieng an drey tag zu regnen, am ersten darnach alle morgen fandt man eyß; wan der morgen vergieng, so wardt der tag ganz warm bis zum endt deß mertzens; der apprill wardt ganz dür und truckhen, das kein reggen noch sehne fiel bis zum endt, der meyen ganz truckhen und schön bis zu dem endt; galt ein fiertel kornj pfund, fueder wein v pfund. Derbrachmonat im anfang ganz truckhen, aber am endt regnet es alle mahl, aber nit vill, und wardt vill heuw; der heuwmonat fieng an ganz dür zu werden so grausam, und werth biß zum endt, daß so ein schröckhliche wassertheüreri anfieng in dißem landt, daß die menschen großen hunger lütten des mahlenshalben, und die frucht …”

English rendering (approximate, based on standard translations used in climate literature):
“In the year 1540. When this year the January was rather cold, then February began warm and dry throughout; March began with three days of rain; thereafter every morning one found ice; when the morning passed, the day became quite warm until the end of March; April was completely dry and arid, so that no rain nor snow fell until the end; May completely dry and fine until the end; a quarter of grain cost 1 pound, a Fuder of wine 5 pounds. June at the beginning completely dry, but at the end it rained every time, but not much, and there was much hay; July began to become completely dry so terribly, and lasted until the end, so that such a dreadful water scarcity began in this land that the people suffered great hunger on account of the milling, and the fruit/crops…”

Later summaries and Wikipedia/climate papers often condense it further: largely dry from mid-February to mid-June (with minor March rain), sunny/warm April–May, some light late-June rain, then scorching hot and rainless from late June into early August, making water scarce and expensive. Conditions remained mild/dry into autumn and early winter with little frost or snow.

A digitized image of the relevant manuscript page (or a reproduction) is available on Wikimedia Commons under “Hans Stolz Tagebuch Guebwiller 1540.png.”

Significance for Climate History

Stolz’s account is prized because:

• It is continuous and locally grounded (Alsace lies in the core drought zone).
• It combines meteorological notes with impacts (water scarcity affecting mills/grinding → hunger; grain and wine prices).
• It aligns closely with other Swiss Plateau, German, and broader European sources used in the Wetter/Pfister et al. (2014) reconstruction of the 11-month megadrought.
• As a vine-grower, he was especially attuned to weather effects on vegetation and harvests.

His chronicle also covers the Peasants’ War era and Reformation tensions in the Upper Rhine valley, making it useful beyond pure climatology.

1540 European megadrought

The 1540 European megadrought (also called the year-round heat and drought of 1540) stands as one of the most extreme hydroclimatic events in European history over the past 500–1,000 years.

It combined prolonged extreme dryness with exceptional heat across much of western and central Europe, peaking as the climax of a notably dry decade (roughly 1531–1540). Climate historians and paleoclimatologists describe it as a “worst-case” or “Black Swan” event relative to modern instrumental records.

The drought lasted approximately 11 months, with sparse rainfall from roughly February through the end of the year (and precursors beginning in late 1539 in southern areas). It affected a vast region of 2–3 million km², including France, the Low Countries, England (London Basin), Germany, Switzerland, Austria, the Czech Lands, Poland, northern and central Italy, parts of Spain, and adjacent areas. Cooler, wetter conditions prevailed farther east (e.g., western Russia).

Precipitation in core areas (e.g., Swiss Plateau and Kraków) fell dramatically—often to roughly one-third or less of 20th-century averages, and below the lowest values recorded in the modern instrumental period for spring, summer, and autumn. Some estimates indicate rainfall deficits of up to 80% in places. The number of precipitation days was exceptionally low.

Reconstructions based on documentary evidence, phenology (e.g., extremely early grape and cherry ripening, second flowering in autumn), and other proxies indicate that annual temperatures were among the highest between 1500 and 2000—potentially 2+ °C above the 1961–1990 baseline in central Europe, with summer maxima likely exceeding 40 °C in some locations due to soil desiccation amplifying heat (land–atmosphere feedback). The summer of 1540 is often compared to (and in some assessments exceeded) the 2003 European heatwave in intensity and duration.

It occurred amid the Little Ice Age, a generally cooler period, making the anomaly especially striking. Contemporary descriptions and modern analysis point to a persistent high-pressure system (an omega block) that stalled Atlantic weather systems for months, allowing hot, dry continental air to dominate while blocking moist westerlies.

Major rivers (Rhine, Elbe, Seine, Meuse, Oder, and others) dropped to ~10% of average discharge in places; people could wade or ride across them. Lake Constance reached record lows (exposing Roman coins and temporarily connecting Lindau to the mainland). Smaller streams and wells dried completely; digging >1.5 m into some riverbeds yielded no water.

Widespread forest, wild, and settlement fires—the highest number of town fires in a peacetime year since at least 1000 CE in German lands. The Einbeck fire alone killed 100–500 people.

Soils cracked deeply; trees shed leaves early; crops and pastures suffered (though some grain harvests held up better than expected in parts of central Europe). Vineyards produced exceptionally sweet “once-in-a-millennium” wine in places (e.g., Würzburg), as grapes partially raisined. Hay and fodder shortages led to livestock deaths from thirst and heat.

Algal blooms in some rivers; fish kills; later locust invasions in following years.

Water scarcity halted mills (disrupting flour production), raised prices for staples, and forced rationing or paid access to remaining wells.

Contaminated residual water sources fueled dysentery and related epidemics.

Estimates of excess deaths vary widely—commonly around half a million across Europe (primarily from disease), with some extrapolations higher (e.g., based on later analogous events).

Social tension rose: paranoia about arsonists (Mordbrenner), scapegoating of migrants or religious opponents, and increased local conflicts.

Martin Luther and others interpreted the conditions in apocalyptic terms.

Remarkably, society recovered relatively quickly with limited long-term demographic or economic collapse—unlike some subsequent cold/wet famine years of the late 16th century. Harvests and populations rebounded in many areas.

The event is reconstructed primarily from over 300 first-hand documentary sources (chronicles, diaries, official records, rogation ceremonies, phenological notes) spanning multiple countries, supplemented by tree-ring data (Old World Drought Atlas), grape-harvest dates, and other proxies.

Key works include Wetter, Pfister et al. (2014) in Climatic Change (“a worst case”) and related papers by Pfister, Brázdil, and others. Tree-ring signals sometimes understate the intensity compared to documentary evidence, leading to scholarly discussion. Climate models struggle to fully reproduce an event of this severity.

It is frequently invoked as a historical analogue when discussing modern European droughts and heatwaves (e.g., 2003, 2018, 2022), highlighting risks from prolonged blocking patterns, soil-moisture feedbacks, and cascading impacts on water, energy, agriculture, and health in a warmer climate.

For deeper reading, start with the 2014 Wetter et al. paper, Pfister’s “Black Swan of 1540” chapter, the Wikipedia synthesis, and Smithsonian or similar popular summaries drawing on the primary research. Regional chronicles (such as Hans Stolz’s from Alsace) provide vivid local detail.

STOLTZ (STOLZ) Hans