Arenal Weather in September
What's the weather like in Arenal (Yoro) in September 2025?
The climate in Arenal during September can be summarized as hot, humid and wet.
September is in the fall / autumn in Arenal and is typically the 3rd warmest month of the year. Daytime maximum temperatures average around a steamy 30°C (86°F), whilst at night 21°C (70°F) is normal.
| Daytime temperature | 30.1°C 86.1°F |
|---|---|
| Nightly temperature | 21°C 69.7°F |
| Average temperature | 25.5°C 77.9°F |
| Daily sunshine | 8 hrs |
| Avg rainfall | 134 mm 5.3 ins |
| Rainy days | 19 days |
| Sea temperature | 29.4°C 85°F |
| Humidity | 76% |
| Windspeed | 20.2kph 13 mph |
On average September is the 3rd wettest month of the year in Arenal with around 134mm 5.3 inches of rain making it a wet time to visit. This rainfall is typically spread over 19 days, although this may vary considerably.
On the flip side this corresponds to an average of 8 hours of sunshine per day.
September temperatures in Arenal
September rainfall
September hourly sunshine
The data used in these monthly averages covers a period of over 100 years right up until last year. As such they are a valid prediction of what to expect for the weather in Arenal in September 2025.
Other monthly averages
Best places to visit in September
Arenal weather stats
| Hottest month: | May | 30.7°C 87.3°F |
|---|---|---|
| Driest month: | March | 27mm 1.1ins |
| Sunniest month: | April | 10.9hrs |
| Coldest month: | January | 26.1°C 79°F |
| Wettest month: | June | 152mm 6ins |
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