The shower officially begins on December 7th, but it doesn't peak until the morning of the14th around 3 a.m. PST (1100 UT). Unlike the Leonids, the Geminid's broad maximum lasts nearly a full day, so observers around the globe have a good chance to see the show. At its peak the Geminids could produce as many as one shooting star every 30 seconds.
Geminid Observing Tips
The maximum of the Geminid meteor shower is expected on the morning of Dec. 14, around 0300 PST (1100 UT). However, the maximum is broad and substantial numbers of meteors may be seen for a 48 hour period around the maximum. Die-hard meteor enthusiasts usually observe this shower all the way from Dec. 7th until Dec. 17th!
Geminid meteors can be seen anytime after 10 p.m. local time, when the constellation Gemini is well above the horizon. The rate will increase greatly after midnight when the local sky is pointing directly into the Geminid meteoroid stream. The best time to look will be during the early morning hours between about 2 a.m. and dawn.