There really is no bad time to visit Mexico, but certain times of the year may appeal to different people more than others, and some destinations may be better at certain times of the year.
Summer, from June to October, is in theory the rainy season in Mexico, but just how wet it is varies wildly from place to place. In the heart of the country you can expect a heavy but short-lived downpour virtually every afternoon; in the north hardly any rain falls, ever. Along the beaches, September to mid-October is hurricane season – you’ll usually get wet weather, choppy seas and mosquitoes, if not a full-on tropical storm. Late winter is the traditional tourist season, worth considering when thinking about the best time to visit, and in the big resorts like Acapulco and Cancún, the months from December through to April are the busiest. Mountain areas, though, can get very cold then; in fact, nights in the mountains can be extremely cold at any time of year.