The weather in San Juan in September is very hot. The average temperatures are between 26°C and 30°C, drinking water regularly is advisable.
You can expect rain for roughly half of the month of September in San Juan. We’re expecting roughly 8 to 15 days of rain, so your rubber boots and umbrella are going to see plenty of use this month if you’re keen on staying dry.
Our weather forecast can give you a great sense of what weather to expect in San Juan in September 2025.
If you’re planning to visit San Juan in the near future, we highly recommend that you review the 14 day weather forecast for San Juan before you arrive.
Temperatures
30° / 26°
Rainy Days
9
Snowy Days
0
Dry Days
21
Rainfall
197
mm
Sun Hours
11.3
Hrs
