Vienna sets records for heat days and summer temperatures

Vienna recorded its hottest summer and its highest number of heat days since measurements began, ORF reported on Monday. The city reached 40 degrees Celsius for the first time, on four separate days.

At the Hohe Warte measurement garden operated by GeoSphere Austria, daily maximum temperatures have been recorded since the mid-19th century. This year, 48 days with temperatures of at least 30 degrees were measured, already three more than during the whole of 2024, previously Vienna’s hottest summer.

The summer’s average temperature also reached a record high. It was nearly three degrees above the average of the recent past, making summer 2026 by far the warmest on record in Vienna and well above the previous warmest summers of the 2000s.

Dry conditions also worsened. Every month this year except February was drier than usual, and around 180 litres of rain per square metre would be needed to make up the rainfall deficit that has built up since March.

Sunshine was less unusual by comparison, with a six percent surplus, equivalent to about 50 additional hours.

The effects of the heat and drought are visible across the city. Lawns and park areas have dried out, while some trees, including trees along Wiedner Gürtel, have had no leaves since mid-August.

Vienna’s municipal gardens department said trees can shed their leaves after prolonged heat and drought to reduce the surface area from which water evaporates. This can also happen to healthy trees, which may recover next year if rainfall returns.

The heat also drove the number of heat-related deaths to a record level. According to the Agency for Health and Food Safety, 646 heat-related deaths were recorded across Austria in June and July alone. Figures for August were not yet available.