WEATHER · CLIMATE NORMALS · 1991–2020
Monterrey Climate — Averages by Month
What the weather in Monterrey, MXaverages across a standard 30-year period. Each month's figure is the 1991–2020 mean temperature and total rainfall from the ERA5 reanalysis — the long-run normal a place settles around, not a forecast for any particular day.
Month-by-month normals
| Month | Avg temperature | Avg rainfall |
|---|---|---|
| January | 14.0 °C · coldest | 40.7 mm |
| February | 16.5 °C | 36.1 mm |
| March | 19.6 °C | 49.6 mm |
| April | 22.9 °C | 49.3 mm |
| May | 25.6 °C | 56.8 mm |
| June | 27.5 °C | 41.8 mm |
| July | 27.9 °C | 46.0 mm |
| August | 28.1 °C · warmest | 33.9 mm |
| September | 25.3 °C | 122.7 mm · wettest |
| October | 22.1 °C | 63.4 mm |
| November | 17.7 °C | 43.4 mm |
| December | 14.5 °C | 35.9 mm |
How to read these numbers
These are reanalysis normals, not readings from a single weather station. They come from the ERA5 0.25° (~25 km) global reanalysis grid, sampled at the grid cell nearest Monterrey — centred at 25.75°N, 100.25°W. A reanalysis blends observations with a physics model onto an even grid, so a coastal or mountain city's cell can read a little cooler, warmer, wetter or drier than the city centre itself. The month-to-month shape — when it's hot, when it rains — is what these normals capture best.
“Normal” means the 1991–2020 average, the current World Meteorological Organization standard period. A normal is what a place tends toward over decades — any single day, month or year can and will depart from it.