The high pressure system which has delivered nearly three weeks of almost unadulterated sunshine and heat is set to loosen its grip from the south of the country as a low pressure system pushes northwards.
This will bring more humid air and a clash which will result in storms, the German Weather Service (DWD) said on Tuesday.
Temperatures will remain high, between 26C and 32C during Wednesday afternoon, and up to 34C in some southern areas. The night will be cloudy in some areas, particularly in the southwest, where some initial showers and even storms are expected.
Those clouds will remain for much of Wednesday in the southwest, with at time heavy rain showers and storms between the Black Forest and the Eifel region in the morning. They will move up towards the Rheinland, southern Hesse and western Franken and Swabia during the rest of the day.
By Wednesday evening hefty storms will cover the country south of a line between the Bavarian Forest and Emsland, while the rest of the country will remain dry and hot, with temperatures between 26 and 32C.
The storms will continue pushing north and west during Wednesday night, with showers and low air pressure pushing temperatures down to as low as 13C in some areas.
Thursday will be sunny at first but clouds will gather in the east and southern mountainous areas, where some storms should be expected. Top temperatures will still remain at between 26 and 32C, dipping only slightly on the Baltic coast to around 25C. The showers and storms will dissipate during Thursday night, when the air temperature will drop to lows of around 13C.
Friday will be sunny again, with isolated but at times strong storms in the west and north west in the afternoon and into the evening. Top temperatures will be between 28 and 34C.