Climate Insights for Arenal

The climate in Arenal is warm and mild. The average annual temperature is 23°C and approximately 1672mm of precipitation falls per year. Arenal receives a notable amount of rainfall throughout the year, including during its driest month. Arenal is in the Northern Hemisphere. Summer begins at the end of June and lasts through September. The summer months are: April, May, September. The coldest months are January, February, December, when temperatures can drop to 16°C.

Arenal sees moderate temperature variation throughout the year, ranging from 16°C to 31°C. The warmest month is April, when average highs reach 31°C and the mean temperature sits around 25°C. January is the coolest month, with minimum temperatures around 16°C and an average of 20°C. On average, daily temperatures fluctuate by about 10°C between overnight lows and afternoon highs.

Arenal is a fairly wet location, receiving approximately 1672mm of precipitation annually, which averages out to around 139mm per month. The wettest month is October, averaging 261mm of rainfall. November and June also tend to see above-average precipitation. The driest month is March, with just 47mm. That's 214mm less than October, the wettest month. Rainfall is heavily concentrated in certain months, creating a distinct wet and dry season. Visitors should plan around these patterns, as the difference between peak and low months is dramatic.

Arenal is relatively calm, with an average annual wind speed of 1km/h. For context, sustained winds below 12km/h are generally light, while anything above 25km/h is considered strong. The windiest month is March, averaging 1km/h, though still comfortable for most outdoor activities. The calmest conditions occur in October, with average winds dropping to 1km/h, making it an ideal period for wind-sensitive activities. There is moderate seasonal variation in wind speed, with a 0km/h gap between the calmest and windiest months.

It is currently summer in Arenal, which began on June 21, 2026. Arenal is in the Northern Hemisphere, where spring begins in March, summer in June, autumn in September, and winter in December. The warmest period peaks in April at around 31°C, while the coldest stretch bottoms out in January near 16°C. Autumn is next, beginning on September 23, 2026 — 91 days from now.

The best time to visit Arenal is during February, March and April, when the weather is most comfortable for travellers. During these months, average temperatures hover around 23°C with modest rainfall averaging 59mm per month. By contrast, January can be quite cold with temperatures dropping to 16°C. A light rain jacket is recommended, though showers are generally brief and shouldn't disrupt your plans.

The table below shows monthly climate averages for Arenal based on historical weather data. Min and max temperatures represent typical overnight lows and afternoon highs for each month, shown in degrees Celsius (°C). Precipitation is measured in millimetres (mm) and indicates the average total rainfall per month. Wind speed is the average sustained speed in kilometres per hour (km/h). All values are based on averages from over 10 years of historical weather data. The current month is highlighted for quick reference.