San José, Costa Rica weather in September
Temperature, rain and sunshine in September: long-term averages from 30 years of weather data, not a forecast.
Holiday weather in September
Fair
Best time to visit: January – March
What is the weather like in San José, Costa Rica in September?
In September, San José, Costa Rica is warm: daytime highs average 24 °C, and nights cool down to about 18 °C. The sun is scarce, with only about 4 hours a day. It rains often – on about 29 days, adding up to 425 mm. The air is often humid and muggy. All in all, September is a so-so month for a holiday in San José, Costa Rica.
September compared
How the weather changes from August to October. Tap a month to open it.
| AugustAug | SeptemberSep | OctoberOct | |
|---|---|---|---|
| Score | 53 | 52 | 51 |
| Day | 25° | 24° | 24° |
| Night | 18° | 18° | 18° |
| Sun | 4 h | 4 h | 3 h |
| Rain days | 26 | 29 | 29 |
More details for September
- Daylight
- 12 h 11 min05:26 – 17:37
- UV index
- 14 · extremeclear sky, noon (estimate)All months
- Muggy days
- 19 daysdew point 18 °C or moreAll months
- Wind
- 7 km/haverage daily peakAll months
- Cloud cover
- 91 %on averageAll months
- Hot days
- 0 days30 °C or moreAll months
- Time zone
- UTC−6America/Costa_Rica
How the score comes together
- Temperatureweight 50 %100 %
- Sunshineweight 20 %10 %
- Few rainy daysweight 30 %0 %
Each factor is rated from 0 to 100 % and weighted for the travel style “City break”.
What to pack in September
- Sunscreen
- Sunglasses & sun hat
- Rain jacket or umbrella
San José, Costa Rica in September: quick answers
Is San José, Costa Rica hot in September?
Warm rather than hot: in September, daytime highs in San José, Costa Rica average 24 °C and nights cool to about 18 °C.
Does it rain much in San José, Costa Rica in September?
It rains often – on about 29 days, adding up to 425 mm.
San José, Costa Rica month by month
The whole year in San José, Costa RicaAll destinations: Costa RicaWhere to go in September
Climate averages 1996–2025, not a forecast. Data: Copernicus ERA5 / ERA5-Land via Open-Meteo.com (CC BY 4.0), NOAA OISST, WMO 1991–2020 (NOAA NCEI), GeoNames (CC BY 4.0). Sources & licences