Mexico City in December: Weather, Air Quality and Holiday Dates

December in Mexico City is dry, sunny and cool. The National Meteorological Service (SMN) 1991-2020 normals for the Tacubaya observatory give an average high of about 22 °C (72 °F), an average low of about 8 °C (47 °F) and only about 5 mm of rain in the whole month, so cold mornings give way to mild afternoons.

How cold does Mexico City get in December?

A typical December day starts near 8 °C at dawn, reaches the low 20s °C by mid-afternoon and cools quickly after sunset, a swing of about 14 degrees Celsius. The contrast with the rainy season shows in the SMN normals for the Tacubaya station:

The western and southern edges of the city sit higher and run colder than the center. When low temperatures are forecast, the city’s risk management and civil protection ministry (SGIRPC) issues color alerts for the early morning: yellow for 4 to 6 °C and orange for 1 to 3 °C. They most often cover high boroughs such as Cuajimalpa, Álvaro Obregón, La Magdalena Contreras, Tlalpan and Milpa Alta, where frost is possible on clear nights.

Cold fronts (frentes fríos) moving south from the United States bring windy, cooler days and the occasional shower. The SMN numbers each front of the season in its daily forecasts, which makes them easy to follow in the news.

Why is the air often worse in December?

The dry winter months bring the year’s highest concentrations of particle pollution (PM10 and PM2.5), according to the city’s air monitoring office. On cold, still mornings, thermal inversions trap a layer of polluted air near the ground, which makes early mornings the worst time for outdoor exercise on bad days.

Holiday smoke adds to it. Fireworks and bonfires on December 24 and 31 push fine particles up overnight, and on January 1, 2026, the Megalopolis Environmental Commission (CAMe) activated an environmental contingency after the New Year celebrations. A contingency adds a second driving restriction to the usual weekly one; our page on Hoy No Circula rules explains which cars stop and what changes on contingency days. Live readings by station are on the city’s air quality website, aire.cdmx.gob.mx, and in its free Aire app.

How many hours of daylight are there?

Mexico City gets about 11 hours of daylight in December, roughly 2 hours and 20 minutes less than at the June solstice. The sun rises between about 6:55 and 7:10 and sets between about 17:55 and 18:10, on Central Standard Time (UTC-6), which the city keeps all year since Mexico ended daylight saving time in 2022.

Times are approximate, calculated for the historic center, and shift by a minute or two across the city. Because sunrise comes after 7:00 for most of the month, school runs and early commutes happen in the coldest, darkest part of the day.

What should you pack or keep at home?

• Layers. A T-shirt for the midday sun, a sweater or fleece, and a warm jacket for mornings and nights out.
• Sun protection. The city sits at about 2,240 meters, and the winter sun is strong at midday, so bring sunscreen, sunglasses and a hat.
• Something for dry air. Lip balm, moisturizer and saline drops help in the driest month of the year.
• Warm bedding. Most apartments have no central heating or insulation, so rooms stay cold overnight. Extra blankets and warm pajamas go further than a space heater.
• Safe heating. If you use a gas heater, keep a window open and never run it while sleeping, because of the risk of carbon monoxide.
• A mask. A well-fitting mask helps sensitive people on bad-air mornings, especially around January 1.

What happens in Mexico City in December?

December is packed with celebrations, yet only two days in the period are official rest days under the Federal Labor Law: December 25 and January 1. The main dates:

For the pilgrimage, road closures and crowds, see our page on December 12 at the Basílica de Guadalupe. Posadas, pastorelas, the Zócalo program and Día de Reyes are in our calendar of Christmas in Mexico City, and the city event and Metro hours for the last night of the year are in our guide to New Year’s Eve in Mexico City.

Two practical effects follow from the calendar. Government offices slow down from mid-December and many take a winter break, so finish paperwork with immigration, tax or city offices early in the month. Travel out of the capital peaks from mid-December to early January, so bus seats and flights fill up.

Bottom line

Dress for about 8 °C at dawn and 22 °C in the afternoon, and get blankets before the first cold front rather than after it. Install the Aire app for the fireworks nights, and book holiday travel and government appointments before mid-December.

FAQ

Does it rain in Mexico City in December?

Rarely. An average December brings about 5 mm of rain on one or two days, according to SMN normals. A passing cold front can still bring a cloudy, drizzly day.

Do apartments in Mexico City have heating?

Most do not have central heating, and many buildings lack insulation. Residents rely on blankets, electric heaters or gas heaters; gas heaters need ventilation because of the carbon monoxide risk.

Is December a bad month for air quality?

Particle pollution peaks in the dry winter months, and thermal inversions make cold mornings worse. The nights of December 24 and 31 are often the worst because of fireworks, so check aire.cdmx.gob.mx before outdoor exercise.

Is December 12 a day off in Mexico City?

Not for most workers. The feast of the Virgin of Guadalupe is not an official rest day under the Federal Labor Law, but banks close and traffic around the Basílica is heavy.