In Poland and other European Union countries, we switch to daylight saving time on the last Sunday of March. On the night of March 27–28, we will move our clocks forward by one hour—from 2:00 to 3:00. As we read in Wikipedia:
Time changes are intended to make more effective use of daylight. In summer, standard geographical time is shifted forward by one hour, so human activity is better aligned with the hours when there is the most sunlight.
On the other hand, the switch to so-called winter time takes place on the last Sunday of October. This year, it will be October 31. We will then turn the clocks back one hour—from 3:00 to 2:00.