Weather is probably a major factor when you plan your trip to Berlin, and keep in mind that cheaper options are usually available when the weather isn't as good. The hottest months are usually March and February with an average temp of 82°F, while the coldest months are December and January with an average of 79°F. The rainiest months in Berlin are October, June, September, and August, with each month seeing an average of 16 inches of rainfall.