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San Juan Weather by Month
Average temperatures, rainfall and humidity for San Juan, Puerto Rico, month by month, built from OpenWeather’s historical records. Use it to see what a typical San Juan month looks like before you travel — then check the live San Juan forecast for the days ahead.
Warmest month
September
31°C average high
Coolest month
January
22°C average low
Wettest month
September
118 mm of rain
Driest month
June
59 mm of rain
Average temperature and rainfall in San Juan by month
Averages of the daily highs and lows recorded in each month, with total rainfall, mean humidity and mean wind speed.
| Month | Avg high | Avg low | Record low / high | Rainfall | Humidity | Wind |
|---|---|---|---|---|---|---|
| January | 28°C | 22°C | 18°C / 31°C | 85 mm | 78% | 15 km/h |
| February | 28°C | 22°C | 19°C / 31°C | 78 mm | 78% | 16 km/h |
| March | 28°C | 23°C | 19°C / 37°C | 75 mm | 76% | 16 km/h |
| April | 29°C | 23°C | 20°C / 33°C | 81 mm | 76% | 16 km/h |
| May | 30°C | 24°C | 20°C / 34°C | 89 mm | 79% | 16 km/h |
| June | 31°C | 25°C | 23°C / 36°C | 59 mm | 78% | 17 km/h |
| July | 31°C | 26°C | 23°C / 35°C | 78 mm | 80% | 18 km/h |
| August | 31°C | 26°C | 23°C / 35°C | 91 mm | 81% | 17 km/h |
| September | 31°C | 26°C | 23°C / 35°C | 118 mm | 80% | 14 km/h |
| October | 31°C | 25°C | 21°C / 35°C | 114 mm | 81% | 13 km/h |
| November | 30°C | 24°C | 21°C / 33°C | 108 mm | 81% | 13 km/h |
| December | 28°C | 23°C | 18°C / 34°C | 86 mm | 79% | 15 km/h |
Best time to visit San Juan
The most comfortable time to visit San Juan is generally January to March, balancing mild daytime temperatures against the driest stretch of the year. Temperatures stay fairly even all year and rain concentrates around September, totalling about 1,064 mm a year.
Travellers who prefer heat should aim for September, when highs average 31°C. September is the month to avoid if rain would spoil your plans — it averages 118 mm, roughly 2× the rainfall of the driest month (June).
Source: OpenWeather historical and statistical weather data. Values are long-term averages, not a forecast — see the San Juan forecast for what is happening now.