Geminids meteors can be seen anytime after 10 p.m. local time, when the constellation Gemini is well above the horizon, but the best time to look is during the early morning hours between about 2 a.m. and dawn. That's when the local sky is pointing directly into the Geminid meteor stream.
Gemini rises about 08:00 p.m. local time at mid-latitudes in the Northern hemisphere. The radiant of the Geminid shower is located near Castor, one of the two bright stars in Gemini (the other bright star is Pollux). To find the constellation at 2:00 a.m., go outside and face south. Castor and Pollux will appear approximately 45 degrees above the horizon. Earlier in the evening, from 10:00 p.m. until midnight, Gemini will be about 30 degrees above the horizon in the southeast.