Climate Insights for San Juan

The climate in San Juan is warm and mild. The average annual temperature is 19°C and approximately 60mm of precipitation falls per year. February is the wettest month, receiving around 10mm of rainfall. San Juan is in the Southern Hemisphere. The seasons are reversed — summer runs from December to February, while winter falls between June and August. The summer months are: March, February, January. The coldest months are August, July, September, when temperatures can drop to 13°C.

San Juan sees moderate temperature variation throughout the year, ranging from 13°C to 27°C. The warmest month is March, when average highs reach 27°C and the mean temperature sits around 22°C. August is the coolest month, with minimum temperatures around 13°C and an average of 16°C. Daily temperature variation is modest, with an average difference of 6°C between highs and lows. The sharpest temperature change occurs between March and April, with a 2°C shift in average temperatures.

San Juan is a quite dry location, receiving approximately 60mm of precipitation annually, which averages out to around 5mm per month. The wettest month is February, averaging 10mm of rainfall. July and August also tend to see above-average precipitation. The driest month is May, with just 3mm. Precipitation varies noticeably between seasons, with the first half (January to June) of the year generally seeing more rainfall.

San Juan is relatively calm, with an average annual wind speed of 4km/h. For context, sustained winds below 12km/h are generally light, while anything above 25km/h is considered strong. The windiest month is August, averaging 4km/h, though still comfortable for most outdoor activities. The calmest conditions occur in June, with average winds dropping to 4km/h, making it an ideal period for wind-sensitive activities. Wind conditions are fairly consistent throughout the year, varying by only 0km/h between the calmest and windiest months.

It is currently winter in San Juan, which began on June 21, 2026. San Juan is in the Southern Hemisphere, where the seasons are reversed — spring starts in September, summer in December, autumn in March, and winter in June. The warmest period peaks in March at around 27°C, while the coldest stretch bottoms out in August near 13°C. Spring is next, beginning on September 23, 2026 — 52 days from now.

The best time to visit San Juan is during January, February, March, April, May, June, July, August, September, October, November and December, when the weather is most comfortable for travellers. During these months, average temperatures hover around 19°C with modest rainfall averaging 5mm per month. With minimal rainfall expected, you can pack light and plan outdoor activities with confidence.

The table below shows monthly climate averages for 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.