Climate averages 1991–2020
San José weather
in September.
A warm, very wet month: the joint 8th warmest and the 11th driest of the year.
Long-term climate patterns, not a forecast for a particular trip.
September is a warm month in San José: daytime highs average 24.2°C and nights cool to about 18.1°C. By daytime temperature it is the joint 8th warmest of the 12 months.
Expect about 391 mm of rain on roughly 29 days, which makes September a very wet month (the 11th driest of the 12 months). Daylight, from sunrise to sunset, lasts about 12 h 11 min on an average September day.
The nearest other city in this atlas is David (247 km away). In September its highs average 27.9°C, 3.7°C warmer than San José, with 460 mm of rain.
From September to October, average highs fall by 0.5°C to 23.7°C, and monthly rainfall rises from 391 mm to 430 mm.
The annual picture
September in context
Monthly rainfall
Average total · mmAverages from hourly ERA5 reanalysis data. Actual weather varies from year to year. How these numbers are calculated
Every month, side by side
San José climate table
| Month | Average highHigh / low | Average low | Rainfall mm/month | Rain days ≥1 mm/day | Daylight hours/dayDaylight h/day |
|---|---|---|---|---|---|
| January | 24.6°C16.8°C | 16.8°C | 104 | 13.3 | 11.612 h |
| February | 25.7°C16.9°C | 16.9°C | 69 | 11.9 | 11.812 h |
| March | 26.6°C17.4°C | 17.4°C | 65 | 13.9 | 12.112 h |
| April | 26.5°C18.1°C | 18.1°C | 102 | 18.0 | 12.312 h |
| May | 25.0°C18.6°C | 18.6°C | 357 | 27.8 | 12.613 h |
| June | 24.4°C18.6°C | 18.6°C | 385 | 28.8 | 12.713 h |
| July | 24.2°C18.3°C | 18.3°C | 293 | 28.2 | 12.613 h |
| August | 24.3°C18.2°C | 18.2°C | 345 | 28.5 | 12.412 h |
| September, selected | 24.2°C18.1°C | 18.1°C | 391 | 29.1 | 12.212 h |
| October | 23.7°C18.1°C | 18.1°C | 430 | 30.1 | 11.912 h |
| November | 23.4°C17.9°C | 17.9°C | 312 | 25.5 | 11.712 h |
| December | 23.8°C17.3°C | 17.3°C | 169 | 17.8 | 11.612 h |
Rainfall is the average of the 30 separate monthly totals. A rain day is a local calendar day with at least 1 mm of precipitation. Daylight is the calculated sunrise-to-sunset length, not measured sunshine.
Compare places
September in nearby cities
- David in SeptemberPanama · 247 kmHigh 27.9°C · Low 21.8°C · 460 mm rain
- Granada, Nicaragua in SeptemberNicaragua · 302 kmHigh 29.4°C · Low 24.5°C · 196 mm rain
- Masaya in SeptemberNicaragua · 316 kmHigh 28.9°C · Low 23.3°C · 196 mm rain
- Managua in SeptemberNicaragua · 340 kmHigh 30.9°C · Low 24.2°C · 168 mm rain
- Matagalpa in SeptemberNicaragua · 388 kmHigh 27.5°C · Low 20.6°C · 167 mm rain
- León, Nicaragua in SeptemberNicaragua · 413 kmHigh 29.7°C · Low 24.1°C · 370 mm rain
- Estelí in SeptemberNicaragua · 430 kmHigh 27.3°C · Low 20.1°C · 227 mm rain
- Chinandega in SeptemberNicaragua · 447 kmHigh 29.9°C · Low 24.4°C · 384 mm rain
Read the numbers correctly
Climate, not a promise.
These patterns help compare months. They cannot tell you the weather on a specific day of your trip.
Sources, method and limitsHow these numbers are made (what the highs, lows and rain days mean, the sources and the model cell used for San José) is explained once on the San José year overview and on the Sources, method and limits page.