San Cristóbal de las Casas weather in September
September in San Cristóbal de las Casas: warm, soaked, with clean air — fine if you can take 27 rainy days.
Updated September 2026 · climate normals from ERA5 reanalysis
#11 of 12 months in San Cristóbal de las Casas · #1051 of 1413 destinations to visit in September · comfort 65/100 (tier C)
- Days
- 25°C
- Nights
- 13°C
- Wet days
- 27
- Sun
- 9.1 h
- Humidity
- 87%
- Daylight
- 12 h
Traveller notes on San Cristóbal de las Casas in September
San Cristóbal's forum describes September rain as genuinely hard to predict - it can be pouring in one town and clear and sunny in the next over these mountain roads, day or night. What's more consistent is the temperature swing: pleasant, jacket-optional days in the low 20s C give way to genuinely cold nights, cool enough that posters recommended a proper warm layer for any evening walk. It's a notably different climate from the hot, humid lowlands nearby, which is part of why San Cristóbal draws visitors even in the rainy season.
Other months in San Cristóbal de las Casas
Forum posters describe this high-altitude town (around 7,200ft) as running noticeably cooler than lowland Mexico even outside its coldest months - January highs typically in the mid-60sF with lows near 40F set the baseline, and March, while milder than January, still carries a real overnight chill given the elevation. Posters consistently note most hotels lack central heating, though extra blankets are commonly provided, so packing warm layers for evenings matters regardless of the season. Unlike the summer rainy season - when posters describe reliably sunny days followed by an hour or two of afternoon/evening rain - March sits in the drier part of the year, generally sunny with a lower overall rain chance.
Add your own note from San Cristóbal de las Casas's card on the map.
San Cristóbal de las Casas climate normals — September
Monthly averages from ERA5 reanalysis. AQI is the mean US Air Quality Index for the month.
Crowds in San Cristóbal de las Casas in September
How busy the place itself is — school and mass holidays, the months an editor tagged, and how sought-after the weather makes them. Never part of the comfort score.
BusyIndependence Day, school holidays in 2 of the markets that fill it(estimated)
Peak crowdsBusyShoulder seasonQuiet
Best months for San Cristóbal de las Casas's weather
Ranked by this destination's own climate comfort score across the year — a different thing from how busy it gets (see Crowds above).
Toughest weatherSan Cristóbal de las Casas's weather peaks January–March, best around February.
Best weatherFair weatherToughest weather
What's on in San Cristóbal de las Casas in September
Recurring seasonal events, natural spectacles, closures and holidays — curated and sourced.
- Holiday
Independence Day
15–16 SepNational holidayCrowdedClosuresOn the night of 15 September thousands gather in the main square for the Grito from the balcony of the old municipal palace, followed next morning by a parade. Central streets close to traffic for both. Source ↗
- Season
Wet season
MonsoonRisk27 rainy days and about 440 mm in the month — the real kind of rainy season, not afternoon showers.
from the climate normals
Nearby, and something's on
Within 300 km of San Cristóbal de las Casas — a day trip or a short hop — with something on this month. Never part of the comfort score.
Where is San Cristóbal de las Casas?
San Cristóbal de las Casas in September — FAQ
- Is September a good time to visit San Cristóbal de las Casas?
- September in San Cristóbal de las Casas: warm, soaked, with clean air — fine if you can take 27 rainy days. It ranks #11 of 12 months for San Cristóbal de las Casas on SeasonMap's comfort score (65/100).
- What is the weather like in San Cristóbal de las Casas in September?
- In September, San Cristóbal de las Casas averages a daily high of 24.7°C and a low of 12.5°C, with about 439.7 mm of rain over roughly 26.8 rainy days.
- What is the air quality in San Cristóbal de las Casas in September?
- San Cristóbal de las Casas has a mean US Air Quality Index of about 28 in September.
Within 300 km: Lake Atitlán's Independence Day on 14–15 Sep.