The eastern half of Austria will have the hottest temperatures, between 30 and 37C, but a cold front of Wednesday will see things cooling down to 29C - with rain showers and storms forecast for most of the country. The sunshine returns on Thursday and Friday, but temperatures will have cooled to a comfortable 26C.
Austria's weather forecaster, the ZAMG, has warned people to avoid spending time at lakes on Wednesday as strong winds and lightning could be dangerous for those close to the water.
"In Salzburg and Upper Austria we will be issuing warnings as soon as we see indications of gusts of more than 60km per hour. At that point storm warning lights will be switched on at affected lakes. This is a signal that anyone on the lake, such as swimmers, boaters and water sport enthusiasts, must immediately get to shore,” Alexander Ohms from the ZAMG Salzburg said.
He added that a fast and efficient warning system was necessary as thunderstorms are hard to predict in hot weather, and often the ZAMG only has 30 to 60 minutes advance notice of a storm.