Berlin has a very moderate historic climate, as you can see from the temperature chart below.
Berlin gets an average of about 33 inches of precipitation, about a quarter is winter snow.
June, July and August are the most popular months to visit Berlin, so summer travelers might want to spend the dog days in the city. Despite the historic highs you see in the charts, it's not unusual to see days in the mid 80s in the summer. Berlin's weather is known to be rather changeable, so be prepared. Rain is pretty evenly divided through the year, and peaks at relatively low levels in summer.
September and October can be fine months to spend in Berlin, as the temperature cools dramatically from the warmer June-July-August plateau.
Winter is chilly in Berlin, with January being the coldest month, when Berlin experiences only 46 hours of sunshine. December's cold doesn't deter tourists bent on visiting the Christmas markets that actually start in November.
The charts below show the historic, monthly high and low temperatures and the month by month average rainfall in Berlin.