Daylight Saving Time (DST) rules
Central European Standard Time = GMT+1
Central European Summer Time = GMT+2
Berlin Time is in the Central European Time Zone
Like most cities in Europe, Summer (Daylight Saving) Time is observed in Berlin, where the time is shifted forward by 1 hour and it is 2 hours ahead of GMT ( GMT+2) .
After the Summer months the time in Berlin is shifted back by 1 hour to Central European Time (CET) or GMT+1 )