Climate Overview
The climate in Río San Juan is warm and mild. The average annual temperature is 25°C and approximately 1347mm of precipitation falls per year. Río San Juan receives a notable amount of rainfall throughout the year, including during its driest month. Río San Juan is in the Northern Hemisphere. Summer begins at the end of June and lasts through September. The summer months are: September, June, August. The coldest months are January, February, March, when temperatures can drop to 19°C.
Temperature
Río San Juan sees moderate temperature variation throughout the year, ranging from 19°C to 31°C. The warmest month is September, when average highs reach 31°C and the mean temperature sits around 26°C. January is the coolest month, with minimum temperatures around 19°C and an average of 23°C. Daily temperature variation is modest, with an average difference of 8°C between highs and lows.
Precipitation
Río San Juan is a fairly wet location, receiving approximately 1347mm of precipitation annually, which averages out to around 112mm per month. The wettest month is September, averaging 152mm of rainfall. November and October also tend to see above-average precipitation. The driest month is January, with just 73mm. That's 79mm less than September, the wettest month. Rainfall is relatively evenly distributed throughout the year, so there is no pronounced dry or wet season to plan around.
Wind
Río San Juan is mildly breezy, with an average annual wind speed of 13km/h. For context, sustained winds below 12km/h are generally light, while anything above 25km/h is considered strong. The windiest month is July, averaging 15km/h, though still comfortable for most outdoor activities. The calmest conditions occur in November, with average winds dropping to 11km/h, making it an ideal period for wind-sensitive activities. Wind conditions are fairly consistent throughout the year, varying by only 4km/h between the calmest and windiest months.
Seasons
89 days until Summer
It is currently spring in Río San Juan, which began on March 20, 2026. Río San Juan 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 September at around 31°C, while the coldest stretch bottoms out in January near 19°C. Summer is next, beginning on June 21, 2026 — 89 days from now.
Spring
Temperatures range from 20 to 30°C. Rainfall is heavy, totalling around 347mm across the season with a monthly average of 116mm. Winds are generally light, averaging 13km/h. An umbrella or waterproof jacket is advisable as spring showers are frequent.
Summer
Temperatures range from 23 to 31°C. Rainfall is heavy, totalling around 342mm across the season with a monthly average of 114mm. Winds are generally light, averaging 14km/h. Light, breathable clothing is ideal — perfect conditions for outdoor activities.
Autumn
Temperatures range from 21 to 31°C. Rainfall is heavy, totalling around 427mm across the season with a monthly average of 142mm. Winds are generally light, averaging 12km/h. A waterproof jacket and sturdy footwear are recommended as rain becomes more frequent.
Winter
Temperatures range from 19 to 28°C. Precipitation is moderate at around 230mm for the season, averaging 77mm per month. Winds are generally light, averaging 12km/h. A light jacket or sweater is usually sufficient, though cooler evenings may call for an extra layer.
Best Time to Visit
The best time to visit Río San Juan is during January, February and December, when the weather is most comfortable for travellers. During these months, average temperatures hover around 23°C with modest rainfall averaging 77mm per month. By contrast, September can be uncomfortably hot with temperatures reaching 31°C. Despite being the best months overall, some rain is still likely — pack a waterproof layer and plan a mix of indoor and outdoor activities.
Monthly Climate Data
The table below shows monthly climate averages for Río San Juan 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.
