Climate averages 1991–2020
São Tomé weather
in September.
A warm, moderately wet month: the joint 9th warmest and the 4th driest of the year. Meets the pleasant-weather rule
Long-term climate patterns, not a forecast for a particular trip.
September is a warm month in São Tomé: daytime highs average 25.5°C and nights cool to about 23.8°C. By daytime temperature it is the joint 9th warmest of the 12 months.
Expect about 46 mm of rain on roughly 8 days, which makes September a moderately wet month (the 4th driest of the 12 months). Daylight, from sunrise to sunset, lasts about 12 h 07 min on an average September day.
The nearest other city in this atlas is Port-Gentil (257 km away). In September its highs average 27.3°C, 1.8°C warmer than São Tomé, with 34 mm of rain.
From September to October, average highs rise by 0.3°C to 25.8°C, and monthly rainfall rises from 46 mm to 152 mm.
The annual picture
September in context
Monthly rainfall
Average total · mmAverages from hourly ERA5 reanalysis data. Actual weather varies from year to year. How these numbers are calculated
Every month, side by side
São Tomé climate table
| Month | Average highHigh / low | Average low | Rainfall mm/month | Rain days ≥1 mm/day | Daylight hours/dayDaylight h/day |
|---|---|---|---|---|---|
| January | 26.9°C24.9°C | 24.9°C | 135 | 23.6 | 12.112 h |
| February | 27.5°C25.4°C | 25.4°C | 115 | 19.4 | 12.112 h |
| March | 27.8°C25.7°C | 25.7°C | 133 | 20.5 | 12.112 h |
| April | 27.6°C25.7°C | 25.7°C | 130 | 18.7 | 12.112 h |
| May | 26.8°C25.2°C | 25.2°C | 119 | 17.0 | 12.112 h |
| June | 25.5°C24.1°C | 24.1°C | 23 | 4.0 | 12.112 h |
| July | 24.9°C23.3°C | 23.3°C | 7.7 | 2.0 | 12.112 h |
| August | 25.0°C23.3°C | 23.3°C | 14 | 2.6 | 12.112 h |
| September, selected | 25.5°C23.8°C | 23.8°C | 46 | 7.8 | 12.112 h |
| October | 25.8°C24.2°C | 24.2°C | 152 | 21.5 | 12.112 h |
| November | 26.1°C24.4°C | 24.4°C | 210 | 25.7 | 12.112 h |
| December | 26.5°C24.6°C | 24.6°C | 174 | 26.1 | 12.112 h |
Rainfall is the average of the 30 separate monthly totals. A rain day is a local calendar day with at least 1 mm of precipitation. Daylight is the calculated sunrise-to-sunset length, not measured sunshine.
Compare places
September in nearby cities
- Port-Gentil in SeptemberGabon · 257 kmHigh 27.3°C · Low 23.6°C · 34 mm rain
- Libreville in SeptemberGabon · 303 kmHigh 27.6°C · Low 23.4°C · 151 mm rain
- Owendo in SeptemberGabon · 309 kmHigh 28.3°C · Low 23.1°C · 123 mm rain
- Bata in SeptemberEquatorial Guinea · 378 kmHigh 27.1°C · Low 22.9°C · 245 mm rain
- Malabo in SeptemberEquatorial Guinea · 443 kmHigh 26.8°C · Low 24.3°C · 384 mm rain
- Kribi in SeptemberCameroon · 456 kmHigh 26.2°C · Low 23.3°C · 335 mm rain
- Ciudad de la Paz in SeptemberEquatorial Guinea · 476 kmHigh 26.9°C · Low 20.1°C · 266 mm rain
- Ogbia in SeptemberNigeria · 486 kmHigh 27.8°C · Low 22.9°C · 339 mm rain
Read the numbers correctly
Climate, not a promise.
These patterns help compare months. They cannot tell you the weather on a specific day of your trip.
Sources, method and limitsHow these numbers are made (what the highs, lows and rain days mean, the sources and the model cell used for São Tomé) is explained once on the São Tomé year overview and on the Sources, method and limits page.