The hot, tropical nights of the past week have meant water temperatures have continued to rise. The warmest water is currently in Carinthia's lakes, where Klopeiner See and Turnersee are around 29C. Experts say smaller lakes in Carinthia could soon hit 30C if the heat continues.
In Vienna, a plunge in the Alte Donau river won't leave you gasping for breath or complaining of goose bumps, with the water temperature now 28C. The Neusiedler See in Burgenland is also on the warm side, with 27C.
The Lunzersee lake in Upper Austria promises to be more refreshing with 25C. And for those desperately seeking a place to cool down Hallstätter See in Upper Austria could be the right place, with just 23C.
Salzburg's lakes are similarly warm - with temperatures between 23 and 26C. The only exception is the Flachauwinkel bathing lake, which is a chilly 18C. But experts have warned people not to jump into cold water without cooling down from the heat first, as the shock to the circulatory system could have adverse health effects.
In Styria, the coolest lake is the Erlaufsee with 23C. Other lakes in the province are between 24 and 28C. Even Bodensee (Lake Constance) in Vorarlberg is currently 25C. Tyrol's lakes are generally a little cooler, between 21 and 26C, with the exception of Schwarzsee which is now 27C.
The fish aren't suffering from the warmer water temperatures as they swim deeper, to the cooler regions of the lake. So far, an increased growth of algae in the water is not noticeable.
Conditions on Friday and Saturday will continue to be hot and humid, with temperatures reaching 33C and up to 35C in the east, with some rain and thunderstorms forecast. Sunday should see cooler temperatures, of around 26C.