If you can stand the early morning chill, the wee hours of Saturday will be prime viewing time for the Geminid meteor shower, historically one of the most productive showers of the year.

In the Bay Area, the best time will be in the two hours between 3:45 a.m., when the waxing gibbous moon will set, and 5:45, when sunrise lightens the sky.

There isn't a specific place in the sky to look, said Patrick Wiggins of NASA/JPL, as concentrating on one portion of the sky is bound to result in missing others elsewhere.

The Geminids are "cosmic visitors from a long-dead comet," Wiggins said, and most are the size of a grain of sand. They burn up and streak across the sky because as they enter the Earth's atmosphere, they compress the air in front of them, generating heat and igniting.

Radiating from near the bright stars Castor and Pollux in the constellation Gemini the Twins, the Geminid meteor shower is one of the finest meteors showers visible in either the Northern or the Southern Hemisphere. The meteors are plentiful, rivaling the August Perseids, with perhaps 50 to 100 meteors per hour visible at the peak.