Mexico City’s altitude means it is mild all year — daytime highs of 21 to 27°C in almost every month — and the real variation is rain and air.
Dry season, October to April
The better half of the year. Sunny days, cool to cold nights, and very little rain.
October and November are the best of it: the rains have cleared the air, the countryside is green, and Day of the Dead falls at the start of November.
December and January are the coolest, with mornings around 6°C, and heating is rare in older buildings.
February to May is the warmest and driest, and also when air quality is at its worst — the basin traps pollution and contingencia ambiental episodes are declared on the worst days.
Rainy season, June to September
Not the problem it sounds. The pattern is a bright morning, cloud building through the afternoon, and a heavy downpour around five or six, often over within an hour or two.
Plan outdoor things for the morning and be indoors at five and it barely affects a trip. The city is at its greenest, the air is clean, and it is the low season for prices.
Streets flood quickly when it does rain, and drainage struggles.
Day of the Dead
31 October to 2 November, and now the peak season in Mexico City. The parade, the ofrendas and the cemetery vigils — see its own entry.
Book months ahead.
Other dates
6 January — Día de Reyes, when the rosca de reyes is eaten and children receive gifts.
Semana Santa — Easter week, when the city empties as people travel and a great deal closes. The Iztapalapa Passion Play draws enormous crowds.
1 May — Labour Day, with large marches on Reforma.
15–16 September — Independence Day. The president rings Hidalgo’s bell and delivers El Grito from the National Palace balcony to a packed Zócalo on the night of the 15th, followed by a military parade on the 16th. The largest public event of the Mexican year.
19 September — the national earthquake drill, and the anniversary of both 1985 and 2017.
12 December — the feast of the Virgin of Guadalupe, and the largest religious gathering in the Americas.
What to pack
Layers, always. The temperature swing between a sunny afternoon and a clear night at 2,240 metres is substantial, and buildings are not heated.
Sun protection — the UV at this altitude is stronger than the mild temperature suggests.
An umbrella or a light waterproof from June to September.