Weather will likely play an important role when you plan your trip to Berlin, but bear in mind that cheaper options are usually available when the weather isn't as good. The hottest months are usually August and September, with an average temperature of 25°C, while the coldest months are February and January, with an average of 22°C. The rainiest months in Berlin are September, October, May and August, with each month seeing an average of 248 mm of rainfall.