GMT problem for CZ

One time I solved this complication. I need to know difference of time between Prague (GMT +1) and the rest of the world. Complication was evocated by summer time. Summer time has been established for reducation of energy wasting. Summer time has no any effect for energy wasting now.

Nobody knew which time is right (summer or winter).

Solution:
Right time is Winter time (GMT +1).
Wrong time is summer time (GMT +2)