Large heat becomes unlikely in Vienna from mid-August

Large-scale heat is expected to become unlikely in Vienna from the second half of August, according to ORF meteorologist Kevin Hebenstreit. The forecast follows a heatwave that produced record temperatures in the Austrian capital and surrounding areas.

Austria recorded a new heat high for the second consecutive day on Wednesday, with 41.2 degrees Celsius measured in Bad Deutsch-Altenburg in the Bruck an der Leitha district. It narrowly surpassed the 41 degrees recorded in Vienna’s Stammersdorf wine-growing area on Tuesday.

The daytime heat also brought record overnight temperatures to Vienna. The city’s Inner District weather station recorded 27.4 degrees during the night to Wednesday, the warmest night since measurements began.

Temperatures are expected to fall by more than 10 degrees in Vienna by Friday. Hebenstreit described this as a significant drop relative to the current heat, although temperatures should still reach around 30 degrees. Thursday is expected to become increasingly humid, with a maximum of 35 degrees and a chance of thunderstorms in the afternoon.

Temperatures are forecast to rise again after Thursday and Friday, reaching between 31 and 33 degrees over the weekend. The weather could stabilise next week, with temperatures of up to 35 degrees and slightly higher values possible towards the end of the week. Apart from possible thunderstorms on Thursday, Friday and at the beginning of next week, little rain is expected.

Stammersdorf recorded Vienna’s highest temperature in 170 years. Hebenstreit said the weather station is located among vineyards surrounded by brown soil. A study by GeoSphere Austria found that dry grassland can heat up in a similar way to asphalt, meaning the station effectively measures conditions like those above an asphalt surface. Temperatures in the city centre were only slightly lower.

Heat is also felt more strongly in urban areas, where asphalt, building facades and pavements can heat up to as much as 60 degrees during the day. They continue radiating heat in the evening and at night as the air cools, making urban areas warmer than green spaces.

Hebenstreit said it was not possible to predict the weather into early autumn because sufficiently long-range forecasts were unavailable. Historical patterns show that cold-air incursions have occurred repeatedly from the second half of August. The days are now becoming noticeably shorter, improving overnight cooling, and the lower position of the sun will also make prolonged extreme heat very unlikely from mid-August.