The best time to visit Mexico is mid September-mid May, though some parts still have a fair amount of rain in October and November. (It rains most during the summer, but usually not often enough to spoil a vacation.)

Mexico City is chilly in the early morning and at night during the winter. Be prepared for higher humidity in coastal areas and at the inland archaeological sites in the Yucatan peninsula. Summer temperatures there can hover at the 100 F/38 C range with near 100% humidity. The average coastal day temperatures year-round are in the 70s-80s F/23-32 C, with nights in the 60s-70s F/15-27 C. Take a sweater and an umbrella any time of year.