Climate Insights for San Juan

The climate in San Juan is hot. The average annual temperature is 31°C and approximately 94mm of precipitation falls per year. July is the wettest month, receiving around 33mm of rainfall. San Juan sits near the equator, so seasonal temperature differences are minimal throughout the year.

San Juan sees moderate temperature variation throughout the year, ranging from 23°C to 41°C. May is the hottest month, with daytime highs reaching 41°C and an average of 35°C. January is the coolest month, with minimum temperatures around 23°C and an average of 24°C. On average, daily temperatures fluctuate by about 9°C between overnight lows and afternoon highs. The sharpest temperature change occurs between February and March, with a 7°C shift in average temperatures.

San Juan is a quite dry location, receiving approximately 94mm of precipitation annually, which averages out to around 8mm per month. The wettest month is July, averaging 33mm of rainfall. April and May also tend to see above-average precipitation. The driest month is February, with just 0mm. That's 33mm less than July, 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.

San Juan is relatively calm, with an average annual wind speed of 6km/h. For context, sustained winds below 12km/h are generally light, while anything above 25km/h is considered strong. The windiest month is December, averaging 13km/h, though still comfortable for most outdoor activities. The calmest conditions occur in April, with average winds dropping to 3km/h, making it an ideal period for wind-sensitive activities. Wind speeds vary significantly across the year, with a 10km/h difference between the calmest and windiest months. This level of variation is worth factoring into travel plans. Wind tends to pick up during the summer months. The seasonal averages are 5km/h in winter, 4km/h in spring, 8km/h in summer, 4km/h in autumn.

It is currently winter in San Juan, which began on June 21, 2026. San Juan sits near the equator, so the traditional four-season cycle is less pronounced. Temperatures remain relatively stable year-round. The warmest period peaks in May at around 41°C, while the coldest stretch bottoms out in January near 23°C. Spring is next, beginning on September 23, 2026 (16 days from now).

The best time to visit San Juan is during January, when the weather is most comfortable for travellers. During these months, average temperatures hover around 24°C with modest rainfall averaging 2mm per month. By contrast, May can be uncomfortably hot with temperatures reaching 41°C. 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.