Climate averages 1991–2020
Roseau weather
in September.
A hot, wet month: the warmest and the 11th driest of the year.
Long-term climate patterns, not a forecast for a particular trip.
September is a hot month in Roseau: daytime highs average 28.3°C and nights cool to about 26.2°C. By daytime temperature it is the warmest month of the year.
Expect about 113 mm of rain on roughly 17 days, which makes September a wet month (the 11th driest of the 12 months). Daylight, from sunrise to sunset, lasts about 12 h 14 min on an average September day.
The nearest other city in this atlas is Fort-de-France (85 km away). In September its highs average 29.0°C, 0.7°C warmer than Roseau, with 138 mm of rain.
From September to October, average highs fall by 0.3°C to 28.0°C, and monthly rainfall rises from 113 mm to 118 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
Roseau climate table
| Month | Average highHigh / low | Average low | Rainfall mm/month | Rain days ≥1 mm/day | Daylight hours/dayDaylight h/day |
|---|---|---|---|---|---|
| January | 25.9°C24.2°C | 24.2°C | 31 | 12.0 | 11.311 h |
| February | 25.9°C24.0°C | 24.0°C | 19 | 7.0 | 11.612 h |
| March | 26.3°C24.2°C | 24.2°C | 19 | 6.9 | 12.012 h |
| April | 27.0°C24.7°C | 24.7°C | 29 | 8.3 | 12.512 h |
| May | 27.7°C25.5°C | 25.5°C | 44 | 10.2 | 12.813 h |
| June | 27.9°C25.9°C | 25.9°C | 47 | 10.5 | 13.013 h |
| July | 28.0°C25.8°C | 25.8°C | 76 | 16.4 | 12.913 h |
| August | 28.2°C26.0°C | 26.0°C | 99 | 18.4 | 12.613 h |
| September, selected | 28.3°C26.2°C | 26.2°C | 113 | 17.1 | 12.212 h |
| October | 28.0°C25.9°C | 25.9°C | 118 | 19.1 | 11.812 h |
| November | 27.3°C25.4°C | 25.4°C | 101 | 17.1 | 11.411 h |
| December | 26.5°C24.8°C | 24.8°C | 48 | 14.3 | 11.211 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
- Fort-de-France in SeptemberMartinique · 85 kmHigh 29.0°C · Low 26.2°C · 138 mm rain
- Basse-Terre in SeptemberGuadeloupe · 86 kmHigh 30.0°C · Low 26.7°C · 107 mm rain
- Castries in SeptemberSaint Lucia · 151 kmHigh 29.1°C · Low 25.2°C · 104 mm rain
- Saint John’s in SeptemberAntigua and Barbuda · 208 kmHigh 28.7°C · Low 26.2°C · 127 mm rain
- Kingstown in SeptemberSaint Vincent and the Grenadines · 239 kmHigh 28.7°C · Low 26.6°C · 141 mm rain
- Basseterre in SeptemberSaint Kitts and Nevis · 264 kmHigh 28.5°C · Low 26.3°C · 118 mm rain
- Bridgetown in SeptemberBarbados · 310 kmHigh 28.5°C · Low 26.2°C · 133 mm rain
- Saint George's in SeptemberGrenada · 363 kmHigh 28.4°C · Low 26.4°C · 143 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 Roseau) is explained once on the Roseau year overview and on the Sources, method and limits page.