Places › San Juan, PR › September

San Juan in September

A risky month — score 49 of 100

Typical September days in San Juan reach about 89°F with nights near 78°F; rain is frequent — about 18 days see some rain, usually in showers. September is also the statistical peak of Atlantic hurricane season (the season runs June 1–November 30) — the averages hide that risk, so flexible plans matter.

Season note: September falls in Atlantic hurricane season (June 1–November 30), its statistical peak. That is climatology, not a forecast — but it is the one risk the averages cannot show.

What to pack for San Juan in September

• A waterproof shell and shoes you can soak — rain falls on about 18 days in a typical September, so plan an indoor anchor each day.
• Pace the midday hours — about 12 days in a typical September reach 90°F.
• Swimsuit, sandals, and reef-safe sunscreen.

Every packing line is triggered by a number on this page — the rules are on How we pick.

September vs. the alternatives

The whole year in San Juan

Averages are the 1991–2020 climate normals (NOAA National Centers for Environmental Information) for the station named on each page. Rain days = days with at least 0.01 in of precipitation. Daylight is computed for the middle of the month.