Monterrey weather in September
September in Monterrey: sweltering, rainy, with clean air — a great time to visit.
Updated September 2026 · climate normals from ERA5 reanalysis
#9 of 12 months in Monterrey · #903 of 1413 destinations to visit in September · comfort 73/100 (tier B)
- Days
- 31°C
- Nights
- 22°C
- Wet days
- 9
- Sun
- 10.3 h
- Humidity
- 70%
- Daylight
- 12 h
Traveller notes on Monterrey in September
Other months in Monterrey
Forum posters describe Monterrey summer weather as capable of reaching up to 100F, making August one of the hottest, most intense stretches of the year in this northern Mexican city. Posters discussing Mexico's August weather more broadly describe high humidity as a common feature across the country's warmer regions this time of year, with daytime highs elsewhere in the low 30sC and overnight lows staying warm as well. Given the limited destination-specific detail available for Monterrey in August specifically, this note leans on that broader pattern: expect serious heat, real humidity, and the need to plan around air-conditioned spaces during the hottest parts of the day. Posters generally recommend visiting Monterrey outside the peak summer months if avoiding intense heat is a priority.
Forum posters describe February across much of Mexico as generally dry and dusty, with real heat not arriving in earnest until closer to May, before the rains set in - placing February in the milder, drier stretch of the year for inland cities like Monterrey. Posters do flag that nights can still be genuinely chilly this time of year even where days turn pleasant. Posters comparing regions note Mexico's Pacific coast resorts get the warmest, sunniest February weather with the least rain risk, a useful contrast that implies Monterrey itself, being inland and further from the coast's moderating influence, likely runs cooler and more variable than those beach destinations at the same time of year.
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Monterrey climate normals — September
Monthly averages from ERA5 reanalysis. AQI is the mean US Air Quality Index for the month.
Crowds in Monterrey 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.
BusyFestival Santa Lucía, school holidays in 2 of the markets that fill it(estimated)
Peak crowdsBusyShoulder seasonQuiet
Best months for Monterrey'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).
Fair weatherMonterrey's best weather comes in February, March and November — separate windows, not one continuous season.
Best weatherFair weatherToughest weather
What's on in Monterrey in September
Recurring seasonal events, natural spectacles, closures and holidays — curated and sourced.
- Hazard
Summer heat
15 May – 5 Sep · usuallyExtreme heatThe city sits in a bowl of the Sierra Madre and holds its heat well into the night. Outdoor plans move to the early morning, and the reservoirs the city drinks from have run dry in the worst of these summers. Source ↗
- Hazard
Tropical rain and flooding
1 Jul – 15 Oct · usuallyFlood seasonGulf storms that cross the coast dump their rain on the Sierra Madre behind the city, and the Santa Catarina riverbed fills within hours. Gilbert and Alex both did serious damage this way. Source ↗
- Festival
Festival Santa Lucía
20 Sep – 2 Nov · usuallyArts festivalCrowdedNuevo León's biggest cultural festival, two to three weeks of mostly free open-air staging along the Paseo Santa Lucía and the Macroplaza. The dates move each year between late September and early November. Source ↗
Where is Monterrey?
Monterrey in September — FAQ
- Is September a good time to visit Monterrey?
- September in Monterrey: sweltering, rainy, with clean air — a great time to visit. It ranks #9 of 12 months for Monterrey on SeasonMap's comfort score (73/100).
- What is the weather like in Monterrey in September?
- In September, Monterrey averages a daily high of 30.6°C and a low of 21.9°C, with about 81.4 mm of rain over roughly 9 rainy days.
- What is the air quality in Monterrey in September?
- Monterrey has a mean US Air Quality Index of about 47 in September.