Stock exchanges in the U.S. generally open at 9:30 a.m. and close at 4:00 p.m. New York time (EST and EDT). Pre-market trading takes place from 4:00 am to 9:30 am and after-hours trading from 4:00 pm to 8:00 pm.
In German time, American pre-market trading usually takes place from 10:00 a.m. to 3:30 p.m., the New York Stock Exchange and Nasdaq are then open from 3:30 p.m. to 10:00 p.m., and after-hours trading goes until 2:00 a.m. the next morning.
That’s the way it usually is. However, we had changed the clocks last Sunday and therefore the whole trade at the USA markets shifts 1 hour forward in German time. So if you want to start trading today, as usual at 15:30, you will find that the US markets have already been in full swing for an hour. However, this will not remain so, because in one week the clocks will be changed in the USA as well. Then everything is back to the normal. Who sits in Germany and trades on the U.S. markets, must therefore trade only this week at different times.