Extreme weather and climate events (WCs)—including severe frosts, heatwaves, cold and warm waves, and anomalous seasonal conditions—pose significant threats to natural ecosystems and human societies. While numerous reconstructions of average climate variables exist for Poland, detailed analyses of extreme events using documentary evidence remain comparatively scarce. In the context of ongoing global warming, understanding historical extremes is crucial for assessing the natural range of climate variability and anticipating future risks.

In this study, we compile and analyze archival records of extreme cold and warm episodes in Poland from the 11th to the 15th centuries. Three types of documentary sources were utilized: handwritten and unpublished records, published documents, and secondary literature. The database includes detailed information on each event’s occurrence (location/region, time, duration, and intensity index), as well as the exact textual content of the original weather note, the source name, and an evaluation of its quality. Using this dataset, we examine the spatiotemporal distribution, duration, intensity, and frequency of the studied extreme events.

Preliminary results indicate that severe frosts, snowstorms, and ice formation on lakes, rivers, and the Baltic Sea were frequently reported, with an increasing trend toward the later centuries. Similarly, warm extremes (heat and warm waves), though less frequently recorded than cold-related events, became more notable toward the end of the study period. A key factor contributing to this increase is the growing availability of historical sources over time. Our findings also highlight distinct periods of heightened climatic extremes, indicating that extreme events were not uniformly distributed across the studied centuries.

Moreover, a comparative assessment with modern extremes suggests that historical records provide valuable insights into the evolution of WCs under current global warming trends. This research not only enhances our understanding of past climate extremes but also offers a long-term perspective essential for forecasting future climatic hazards.

This work was supported by the National Science Centre, Poland, project No. 2020/37/B/ST10/00710.

How to cite: Akbari Moghaddam Sani, S., Przybylak, R., and Oliński, P.: Documentary Evidence of Past Extreme Weather and Climate Events in Poland in the 11th–15th Centuries, EMS Annual Meeting 2025, Ljubljana, Slovenia, 7–12 Sep 2025, EMS2025-24, https://doi.org/10.5194/ems2025-24, 2025.

Grain prices in early modern Europe reflected the effects of weather and climate on crop yields and a complex array of societal and socio-economic factors. This study presents a newly developed series of grain prices for Sušice (southwestern Bohemia, Czech Republic) for the period 1725–1824 CE, based on various archival sources. It aims to analyse their relationships with weather and climate, represented by temperature, precipitation, and drought (self-calibrated Palmer Drought Severity Index, scPDSI) reconstructions, as well as particular weather extremes and anomalies reported in documentary evidence. Wheat, rye, barley, and oats series in Sušice showed high mutual correlations. The mean highest prices during the year typically occurred from May to July before the harvest, while prices usually declined afterwards. Wheat, rye, and barley prices were significantly negatively correlated with spring temperatures and positively correlated with scPDSI from winter to summer. This indicates that wetter winters, cooler and wetter springs, and wetter summers contributed to higher prices. The extremely high grain prices in the years 1746, 1771–1772, 1802–1806, and 1816–1817 CE were separately analysed with respect to weather and climate patterns and other socioeconomic and political factors. The results obtained were discussed in relation to data uncertainty, factors influencing grain prices, and the broader European context.

This work was supported by the Johannes Amos Comenius Programme and the Ministry of Education, Youth and Sports of the Czech Republic through the project “AdAgriF - Advanced methods of greenhouse gases emission reduction and sequestration in agriculture and forest landscape for climate change mitigation” (CZ.02.01.01/00/22_008/0004635).

How to cite: Brazdil, R., Lhoták, J., Chromá, K., and Dobrovolný, P.: Effects of weather and climate on fluctuations of grain prices in southwestern Bohemia, 1725–1824 CE, EMS Annual Meeting 2025, Ljubljana, Slovenia, 7–12 Sep 2025, EMS2025-449, https://doi.org/10.5194/ems2025-449, 2025.

Public granaries served as key infrastructure to improve food security in agrarian societies. Their history dates to the oldest complex societies, but they experienced a boom period during the 18th and early 19th centuries in Europe. In Bohemia and Moravia (modern-day Czech Republic), numerous granaries were established by decree in 1788 to provide serfs with grain for sowing in the face of fluctuating weather. Here, we analyse granary data from 15 out of a total of 17 considered domains in the Sušice region (southwestern Bohemia) from 1789 to 1849 CE. We use the documented annual values of grain borrowed by serfs, their grain depositions, total grain storage, and the total debt of serfs at the end of the year as proxies for harvest quality and size. Based on the series of these four variables, we calculated weighted grain indices, considering the balance between borrowed and returned grain: a weighted bad harvest index (WBHI), a weighted good harvest index (WGHI), a weighted stored grain index (WSGI: WSGI-, more borrowed than returned; WSGI+, more returned than borrowed), and a weighted serf debt index (WSDI: WSDI+, more borrowed than returned grain; WSDI-, more returned than borrowed grain). WBHI, WSGI-, and WSDI+ were used to select years of extremely bad harvests, while WGHI, WSGI+, and WSDI- were used to identify years of extremely good harvests. We tested selected extreme harvest years against documentary weather data and reconstructed temperature, precipitation, and drought series from the Czech Lands. We discuss the uncertainty in the data and the broader context of the results obtained. The findings document the potential of this new methodology using widely available public granary data as proxies for historical climatological research.

This work was supported by the Johannes Amos Comenius Programme and the Ministry of Education, Youth and Sports of the Czech Republic through the project “AdAgriF - Advanced methods of greenhouse gases emission reduction and sequestration in agriculture and forest landscape for climate change mitigation” (CZ.02.01.01/00/22_008/0004635).

How to cite: Brázdil, R., Lhoták, J., Chromá, K., Collet, D., Dobrovolný, P., and Huhtamaa, H.: Public granaries as a source of proxy data on grain harvests and weather extremes for historical climatology, EMS Annual Meeting 2025, Ljubljana, Slovenia, 7–12 Sep 2025, EMS2025-438, https://doi.org/10.5194/ems2025-438, 2025.

Gdansk, the coastal city in Northern Poland is characterized by an unusually early start of instrumental precipitation measurements. The first isolated measurement series, over 30 years old, dates back to 1739-1772 and was the work of the physicist and mathematician Michael C. Hanow. In the second decade of the 19th century, measurements of precipitation totals were occasionally carried out by a medicine doctor Johann G. Kleefeld. The next period of precipitation measurements, continuing uninterrupted until the present day, began in 1851 and were initiated by Friedrich Strehlke – a head of the St. Peter and Paul School in Gdansk.

Due to the disappearance, most probably irreversible, of Strehlke's original records, it has become impossible to reconstruct the daily precipitation totals from the initial period of measurements. It is possible to do so for the time from 1876 onwards, from the start of the Deutsche Seewarte meteorological station in the Nowy Port (New Harbour/Neufahrwasser) district. However, the complete record of annual and monthly precipitation totals still exist.

The average annual total precipitation in Gdansk in the period 1851-2024 was about 560 mm. The wettest months are July and August, with an average of over 70 mm of precipitation, and the driest are February and March (less than 30 mm of precipitation). No statistically significant changes in precipitation totals were found in Gdansk in the considered period. There are on average 170 days with precipitation of at least 0.1 mm per year. Approximately five times a year more than 20 mm falls per day, while once in four years there is precipitation exceeding 50 mm. The absolute maximum daily precipitation, recorded in Gdansk in 2016, reached 160 mm.

Particularly important task of the paper was a reconstruction of the variability of daily precipitation totals carried out in relation to the earliest of the Gdansk measurement series, i.e. Hanow’s measurements. In addition to daily data, information on the type of hydrometeorological phenomena observed by the researcher was also used, which allowed to improve the reconstructed series values. Several significant incidents of very heavy rainfall were identified during the analyzed period. Another observed feature was the significant dominance of autumn precipitation totals over spring totals, demonstrating the strengthening of the oceanic characteristics of the city's climate in the 18^th century.

The work was done within a NCN project entitled The occurrence of extreme weather, climate and water events in Poland from the 11th to 18th centuries in the light of multiproxy data, supported by the National Science Centre, Poland, project No. 2020/37/B/ST10/00710.

How to cite: Filipiak, J.: Reconstruction of the precipitation series in Gdansk, Poland during the period of instrumental measurements, EMS Annual Meeting 2025, Ljubljana, Slovenia, 7–12 Sep 2025, EMS2025-384, https://doi.org/10.5194/ems2025-384, 2025.