Guanajuato weather by month
Guanajuato runs from about 15°C in January to 25°C in May, with July the wettest month at 215 mm.
warmest month
May
25°C
coolest month
January
15°C
wettest month
July
215 mm
worst air month
March
12 µg/m³
The whole year, month by month.
| Month | Avg temp | Rain | Sun | PM2.5 |
|---|---|---|---|---|
| January | 15°C | 1 mm | 292 h | 10 |
| February | 17°C | 18 mm | 292 h | 9 |
| March | 20°C | 0 mm | 364 h | 12 |
| April | 22°C | 0 mm | 366 h | 10 |
| May | 25°C | 5 mm | 390 h | 11 |
| June | 22°C | 84 mm | 355 h | 7 |
| July | 19°C | 215 mm | 345 h | 9 |
| August | 19°C | 115 mm | 363 h | 7 |
| September | 19°C | 136 mm | 315 h | 6 |
| October | 18°C | 18 mm | 315 h | 7 |
| November | 18°C | 2 mm | 327 h | 9 |
| December | 15°C | 5 mm | 323 h | 9 |
About 4,047 hours of sun a year. Roughly 62 rainy days a year.
These are long-run climate normals, not a forecast. A given year can sit well outside them. PM2.5 is a global model: near the coast it counts sea salt as fine particulate and reads high against ground stations, sometimes by a factor of two. Use the shape of the year, not the absolute number.
where these numbers come from
- · Temperature, rainfall and sunshine: ECMWF ERA5 reanalysis climate normals via Open-Meteo (CC BY 4.0), fetched once and stored.
- · PM2.5: Copernicus CAMS reanalysis, monthly means. Modelled, not station readings; near coasts CAMS counts sea salt as PM2.5 and reads high.
Last reviewed 2026-05-25. Full method, licences and the list of sources we rejected are on the methodology page.