High season in the Yucatán begins around December 20 and continues to Easter. This is the best time for calm, warm weather; snorkeling, diving, and fishing (the calmer weather means clearer and more predictable seas); and for visiting the ruins that dot the interior of the peninsula. Book well in advance if you plan to be in Cancún around the holidays.
Low season begins the day after Easter and continues to mid-December; during low season, prices may drop 20% to 50%. In Cancún and along the Riviera Maya, demand by European visitors is creating a summer high season, with hotel rates approaching those charged in the winter months.
Generally speaking, Mexico's dry season runs from November to April, with the rainy season stretching from May to October. It isn't a problem if you're staying close to the beaches, but for those bent on road-tripping to Chichén Itzá, Uxmal, or other sites, temperatures and humidity in the interior can be downright stifling from May to July. Later in the rainy season, the frequency of tropical storms and hurricanes increases; such storms, of course, can put a crimp in your vacation. But they can lower temperatures, making climbing ruins a real joy, accompanied by cool air and a slight wind. November is especially ideal for Yucatán travels. Cancún, Cozumel, and Isla Mujeres also have a rainy season from November to January, when northern storms hit. This usually means diving visibility is diminished -- and conditions may prevent boats from even going out.
Villahermosa is sultry and humid all the time. San Cristóbal de las Casas, at an elevation of 2,152m (7,059 ft.), is much cooler than the lowlands and is downright cold in winter.
