Not too difficult to get the hang of really, though it varies from person to person.
I myself, have 2 clock widgets on my desktop, one in local time, the other in UTC (superseded GMT in 1972 as the "Universal time", however they are both in the same). My local time is Eastern, which is GMT/UTC -05, however, this Sunday, it will go to GMT/UTC -04, after Daylight Savings Time goes into effect.
Regardless of if GMT still advances an hour in the summer or not, I think this doesn't happen until the 27th, so there is still an hour difference for a few weeks.