I live in southern California now, but I'm a New York City native. My best advice is to check a reliable online weather forecast - one of the best is http://www.weather.gov - and go from there. That's because NYC's weather can be highly variable from year to year. For example, normally there isn't snow till around Christmas time or early January. Not this year, however. NYC got snowed on in late October.
Heart of the City Run, Los Angeles, CA, 24:13
Downtown Anaheim 5K, Anaheim, CA, 24:32
Claremont Turkey Trot, Claremont, CA, 24:20
The Great Race - Old Agoura 10K, Agoura Hills, CA, 51:12
Fiesta Days Run, La Canada, CA, 49:31
LA Cancer Challenge, West Los Angeles, CA, 51:21
Long Beach International City Bank Half Marathon, Long Beach, CA, 1:54:31