Mexico - weather in December

December is the first winter month in the Northern Hemisphere. In Mexico, a very extensive country, crossed by the Tropic of Cancer in the central part, it is a very mild month in the plains and coasts of the north, and warm in the south.
However, in the mountains of the north (Sierra Madre Occidental and Sierra Madre Oriental) it is cold. In the northern plateau (see Ciudad Juárez, Chihuahua), where we find the Chihuahua Desert, it gets cold at night as well.
Furthermore, December is generally the coolest month of the year in the westernmost part of Mexico (see the states of Baja California, Baja California Sur and Sonora), while January is the coolest month in the rest of the country.
During winter, the Norte can blow from the United States, a cold wind capable of abruptly lowering the temperature, especially in the center-north. Because of this wind, the inland areas of the north (a little less the coastal areas) can experience cold waves during the winter, with snowfalls and frosts, especially in hilly and mountainous areas.
In the south it is warm even in winter, but only on the coasts and in the lowlands (the tierras calientes). The hottest and sunniest area is the southern coast, facing the Pacific (see Acapulco), while the coast of the Gulf of Mexico (see Veracruz) can receive a bit of cool air from the north. The Yucatán peninsula (see Mérida, Campeche) is warmer, but there can be cool and windy days, and even some rain, especially on the eastern side, in Cancún and the Riviera Maya.
Instead, on the plateaus, especially above 2,000 metres (6,500 feet), in the tierras frìas, there is a considerable thermal excursion, and it gets cold at night. In the highest volcanoes, the average temperature is just above freezing at 4,000 metres (13,000 ft).
Generally, winter in Mexico is a dry season, however, as mentioned, there can be some rains in Yucatán, and this is even more true in northern Chiapas (see Palenque).
Even in the northwest, in the western part of Baja California (see Tijuana), where the climate has Mediterranean characteristics, it can sometimes rain.
Mexico is located at fairly low latitudes, however, December is the month with the shortest days, about 10 hours in the north and 11 hours in the south. December 21 is the winter solstice, that is, the shortest day of the year in the Northern Hemisphere.

The sea is warm enough for swimming on the coast of the Gulf of Mexico, where it is around 23 °C (73 °F) in the northernmost part (see Matamoros). On the Pacific coast, it is quite warm from about the latitude of the Tropic (see Culiacán, Mazatlán), and in the southernmost part of the California peninsula (see Los Cabos), while it is very warm in the southernmost part (see Acapulco).
Instead, to the west, in the Baja California peninsula, the sea is cold in the northern part, where a cold current flows.




See also: Mexico, the weather in November - January
The climate of Mexico