Early Season Heatwave in Central Europe, Temperatures 5-10°C Above Normal on June 4th

Between June 3rd and June 5th, 2025, Central and Eastern Europe experienced an early-season heatwave, with temperatures significantly exceeding seasonal averages. Notably, on June 4th, several countries recorded temperatures well above their typical early June norms. For instance, in Austria, Vienna a high of 29.1°C was reached, approximately 5°C above the average for this time of year. Similarly, Bratislava, Slovakia, saw temperatures peak at 29.8°C, and Budapest, Hungary, recorded a high of 31.5°C, both exceeding their usual early June temperatures by about 5–7°C. In Zagreb, Croatia, the temperature soared to 31.1°C, also notably above the seasonal average. The image below shows the effects of the heatwave as it pushed through Central and Eastern Europe, with swaths of the region experiencing significantly higher temperatures as compared to normal. Parts of the Alps in Germany and Austria experienced temperatures over 10°C above seasonal norms.

The Czech Republic and Poland also experienced significant temperature anomalies. Prague recorded a high of 27.4°C on June 4th, which is approximately 5°C above the typical early June temperature. In Warsaw, the temperature reached 27.3°C, surpassing the average by about 5°C. These elevated temperatures are particularly concerning given the early point in the summer season. The early-season heatwave may be foreboding extreme temperatures later in the season.

Nighttime temperatures during this period remained unusually high, offering little respite from the daytime heat. In Budapest, the minimum temperature on June 4th was 13.3°C, while in Vienna, it was 13.9°C. Although these figures may not seem extreme, they are higher than the typical early June nighttime lows, indicating a trend of persistently warm conditions. While no all-time or monthly records were officially broken during this specific period, the significant deviations from average temperatures across multiple countries underscore the intensity of this early-season heatwave. The sustained high temperatures, both during the day and at night, highlight the increasing frequency and severity of heatwaves in Europe, aligning with broader patterns of climate change in the European continent. The Northern Hemisphere summer season is still young and another heatwave in Central and Eastern Europe is inevitable. Whether that heatwave is comparatively mild or leads to new record temperatures is yet to be seen.