Poland is in the Central European Time Zone which is 1 hour ahead of Greenwich Mean Time (GMT+1). This time zone is used in majority of European countries: Spain, France, Germany, Italy, Austria, the Czech Republic, Slovakia, Hungary, Norway, Sweden and a few other countries.
Like most states in Europe, Poland uses Daylight Saving Time. Each year on the last Sunday of March clocks are advanced by one hour to make the most of seasonal daylight. On the last Sunday of October clocks are shifted back by 1 hour. Thus during summer we are 2 hours ahead of Greenwich Mean Time (GMT+2).
The length of day changes throughout the year and depends on the time of year. Days are longest during late spring and summer (from April/May till August/September) and shortest in winter (between October/November and February/March).