As the calendar flips to May, the anticipation for the Eisheiligen, or Ice Saints, begins to build across Germany and Austria. Scheduled from May 11 to May 15, 2025, these days are steeped in tradition and folklore, marking the last potential frost nights before the true arrival of spring. With names like Pankrazi, Servazi, Bonifazi, and Sophie, the Eisheiligen are associated with Catholic saints whose feast days fall within this timeframe, leading many gardeners to hold off on planting sensitive crops until after this period.
In some regions, the day before the Eisheiligen, known as Mamertus Day, on May 11, is also included in this weather phenomenon. According to old regional farmers' sayings, "Pankrazi, Servazi, Bonifazi are three frosty fellows, and in the end, the cold Sophie is never missing." These sayings reflect the belief that frosty nights are likely during these days, a notion that has been passed down through generations.
However, climatologist Alexander Orlik from GeoSphere Austria has shed light on changing weather patterns. He notes that data from the last 80 years indicate that frost does not occur disproportionately during the Eisheiligen. “Frost does not appear more frequently during the Eisheiligen than at other times,” Orlik stated. He emphasized that while the first third of May is typically the most likely time for frost, the risk significantly decreases during the Eisheiligen.
In Austria, ground frost, defined as temperatures below 0 degrees Celsius measured five centimeters above the ground, is becoming increasingly rare. For instance, between 1991 and 2020, Vienna and Salzburg experienced ground frost about once every five years during the first third of May. In contrast, during the last third of May, the likelihood of frost drops to nearly zero in populated areas. In higher altitudes, however, such as Lienz and Irdning, ground frost still occurs, averaging one to two days per year in early May.
The German Weather Service (DWD) has also released forecasts for the Eisheiligen 2025, confirming that while temperatures are expected to be mild, some areas may still experience ground frost, particularly in the eastern and southeastern uplands. For example, on May 11, the night of Mamertus, temperatures in Brandenburg are predicted to drop to between 9 and 0 degrees Celsius, with frost possible in some areas.
As the Eisheiligen approach, the weather across Germany shows variability. In southern regions, widespread rain has been reported, while northern areas enjoy sunny spells. The DWD forecasts indicate that extreme night frosts are not expected, although light frost remains a possibility in certain elevated areas. On May 12, the day of Pankratius, temperatures are expected to drop to 4 to 7 degrees Celsius at night, with highs reaching up to 17 degrees during the day.
The following days, dedicated to Servatius, Bonifatius, and the Cold Sophie, are expected to bring more sunshine, with daytime temperatures ranging from 16 to 24 degrees Celsius. However, nighttime temperatures may still fall into the single digits, particularly in the eastern uplands where it could drop to around 2 degrees.
Despite the tradition of the Eisheiligen signaling the end of frost danger, experts are cautious. The DWD has noted that while widespread frost has become less common, individual years can still bring surprises. As such, gardeners are advised to exercise caution and wait until after the Eisheiligen before planting sensitive plants like tomatoes and peppers.
In recent years, the intensity and frequency of cold spells during the Eisheiligen have diminished due to climate change. The DWD reports that the likelihood of experiencing a cold snap during this period has decreased to about 60 percent. Historical data shows that while the Cold Sophie once brought significant snowfall, such occurrences are now rare.
As gardeners prepare for the planting season, they are reminded of the importance of monitoring weather forecasts closely. Even after the Eisheiligen, ground frost can still occur, making it essential to protect young plants from unexpected cold snaps. Simple protective measures, such as using fabric covers or bringing potted plants indoors at night, can safeguard delicate crops.
In summary, the Eisheiligen remain a significant event in the gardening calendar, symbolizing the transition from winter to spring. While the risk of frost has decreased over the years, the tradition continues to influence planting decisions across Germany and Austria. As the dates approach, both gardeners and weather enthusiasts alike will be watching the skies and temperatures closely, hoping for a smooth transition into warmer days ahead.
