ClimateExplore the planning map
Climate · San Juan

San Juan in September

Hot and wet, as the days shorten.

Typical weather, averaged over 30 years

September in San Juan is hot: highs near 91°F, lows near 76°F. Rain falls on about six days a week, and the days shorten by 22 minutes from the first week to the last.September in San Juan is hot: highs near 33°C, lows near 24°C. Rain falls on about six days a week, and the days shorten by 22 minutes from the first week to the last.

High
91°F33°Caverage
Low
76°F24°Caverage
Wet days
6a week · 80% of days
Daylight
12h 12mon average

Is September a good time to visit San Juan?

September sits outside San Juan's most comfortable months, which run from December to March. Expect hot days and rain on about six days a week.

How we judge it: every month is scored on how close its typical high comes to the range from 70°F to 80°F, how mild its nights are, and how rarely it rains. The best months are the run of months that scores best.How we judge it: every month is scored on how close its typical high comes to the range from 21°C to 27°C, how mild its nights are, and how rarely it rains. The best months are the run of months that scores best.

How September sits in the year

week by week

Temperature

Highs near 91°F in September, against 85°F to 92°F through the year.Highs near 33°C in September, against 29°C to 33°C through the year.

Chance of a wet day

80% of days in September, against 35% to 80% through the year.

Cloud cover

67% cover in September, against 28% to 67% through the year.

Daylight

12h 12m in September, against 11h 03m to 13h 13m through the year.

Week by week, lightly smoothed, with September shaded. The olive line marks the most comfortable months. Hover or tap a week for its figures.

Either side

  1. August92°33°low 77°low 25°5 wet days a weekRain on about five days a week.
  2. September91°33°low 76°low 24°6 wet days a weekRain on about six days a week.
  3. October90°32°low 76°low 24°5 wet days a weekRain on about five days a week.

Where San Juan sits, in September

America/Puerto Rico
this place
typical high in September 40°F4°C95°F35°C
Sunrise, mid-September
6:12 AMsets 6:28 PM
Above the sea
30 mlow-lying
Latitude
18.4°Nnorthern hemisphere
Nearest of ours
Dorado24 km west

The land around San Juan, shaded by its typical high in September, the planning map's own layer. Hover the map for the figure at that spot; tap it on a phone. Clock times are local, for the 15th.

Elsewhere in Puerto Rico in September

high · low · wet days
See September on the planning mapThe whole year in San Juan

Typical weather, averaged over 30 years (1995–2024), from the 11 km grid square nearest San Juan. Temperatures are adjusted against 66 weather stations: daytime highs read about 3.1°F cold in the source data and are raised to match.Temperatures are adjusted against 66 weather stations: daytime highs read about 1.7°C cold in the source data and are raised to match. Daylight is calculated from latitude. Charts are lightly smoothed week to week; the figures in the table are not. Source: Copernicus ERA5-Land reanalysis; cloud cover from NASA's MERRA-2 reanalysis, on a coarser grid of about 50 km. Contains modified Copernicus Climate Change Service information 2026; neither the European Commission nor ECMWF is responsible for any use of it. These are averages, not a forecast.

Daylight is calculated from latitude. Charts are lightly smoothed week to week; the figures in the table are not.

Source: Copernicus ERA5-Land reanalysis; cloud cover from NASA's MERRA-2 reanalysis, on a coarser grid of about 50 km. Contains modified Copernicus Climate Change Service information 2026; neither the European Commission nor ECMWF is responsible for any use of it. These are averages, not a forecast.