Vienna is sweating: the first tropical night of the year brings a heat wave!

Vienna is sweating: the first tropical night of the year brings a heat wave!

On June 5, 2025, Vienna experienced the first tropical night of the year in which temperatures did not drop below 20 degrees. A low temperature of 20.3 degrees was measured at Karlsplatz, while in Podersdorf (Neusiedl district) the minus temperatures were 20.2 degrees. This night temperature is defined as a tropical night, and the forecasts for this day indicated possible hot days, with expected temperatures of around 29 degrees Celsius in Vienna and over 30 degrees in parts of southern Styria, the Graz Basin and Burgenland. 5min.at reports that such tropical nights are more common, especially in urban areas, where the heat island effect causes temperatures to rise additionally.

The health effects of hot days and tropical nights are significant. Children, older people and people with previous illnesses are particularly affected. Heat-related health risks should not be underestimated; According to the Ministry of Health, up to 500 people in Austria die from heat-related complications every year. Prolonged heat can cause cardiovascular problems, which become more severe as temperatures rise. context-institut.at emphasizes that at temperatures above 26 degrees, concentration suffers and the risk of accidents at work increases.

Economic effects of heat

The heat not only causes health problems, but also has economic consequences. Industries that rely heavily on outdoor physical work, such as construction, agriculture and catering, are particularly affected. In these sectors, customers are often absent at lunch and afternoon, which leads to a loss of sales. Additionally, prolonged drought impacts agriculture by reducing water availability and reducing yields. context-institut.at reports on the challenges that persistent drought periods bring, such as the susceptibility of spruce trees to pests due to a lack of water.

Forecasts and future risks

The forecasts show that the number of tropical nights and hot days will increase due to climate change. The German Weather Service defines “hot days” as those with temperatures above 30 degrees. Between 2000 and 2023, the summers of 2003, 2015, 2018 and 2022 were particularly affected by an increase in these hot days. Health risks are increasing as each further increase in temperature can bring heat-related mortality of 1 to 6 percent. umweltbundesamt.de points to the increase in health risks caused by the simultaneous occurrence of hot days and tropical nights as particularly problematic.

The appreciation for cooler places during the summer months is likely to increase in the next few years. Measures should be taken, especially in cities, to counteract the heat and ensure the quality of life of the population. Heat waves, which include several hot days and tropical nights, become not only a health challenge but also an economic burden, requiring appropriate measures at the local and national levels.