Climate averages 1991–2020
Castries 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 Castries: daytime highs average 29.1°C and nights cool to about 25.2°C. By daytime temperature it is the warmest month of the year.
Expect about 104 mm of rain on roughly 19 days, which makes September a wet month (the 11th driest of the 12 months). Daylight, from sunrise to sunset, lasts about 12 h 13 min on an average September day.
The nearest other city in this atlas is Fort-de-France (68 km away). In September its highs average 29.0°C, about as warm as Castries, with 138 mm of rain.
From September to October, average highs fall by 0.5°C to 28.6°C, and monthly rainfall rises from 104 mm to 119 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
Castries climate table
| Month | Average highHigh / low | Average low | Rainfall mm/month | Rain days ≥1 mm/day | Daylight hours/dayDaylight h/day |
|---|---|---|---|---|---|
| January | 26.9°C23.4°C | 23.4°C | 31 | 11.8 | 11.411 h |
| February | 27.3°C23.3°C | 23.3°C | 21 | 8.9 | 11.712 h |
| March | 27.7°C23.5°C | 23.5°C | 26 | 9.8 | 12.012 h |
| April | 28.4°C24.0°C | 24.0°C | 36 | 11.5 | 12.412 h |
| May | 29.0°C24.8°C | 24.8°C | 47 | 12.5 | 12.813 h |
| June | 28.8°C25.0°C | 25.0°C | 65 | 15.1 | 12.913 h |
| July | 28.7°C24.8°C | 24.8°C | 83 | 20.3 | 12.913 h |
| August | 28.9°C25.0°C | 25.0°C | 99 | 20.7 | 12.613 h |
| September, selected | 29.1°C25.2°C | 25.2°C | 104 | 19.4 | 12.212 h |
| October | 28.6°C24.9°C | 24.9°C | 119 | 20.9 | 11.812 h |
| November | 27.8°C24.5°C | 24.5°C | 102 | 18.8 | 11.511 h |
| December | 27.3°C24.0°C | 24.0°C | 42 | 13.0 | 11.311 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 · 68 kmHigh 29.0°C · Low 26.2°C · 138 mm rain
- Kingstown in SeptemberSaint Vincent and the Grenadines · 96 kmHigh 28.7°C · Low 26.6°C · 141 mm rain
- Roseau in SeptemberDominica · 151 kmHigh 28.3°C · Low 26.2°C · 113 mm rain
- Bridgetown in SeptemberBarbados · 179 kmHigh 28.5°C · Low 26.2°C · 133 mm rain
- Saint George's in SeptemberGrenada · 231 kmHigh 28.4°C · Low 26.4°C · 143 mm rain
- Basse-Terre in SeptemberGuadeloupe · 236 kmHigh 30.0°C · Low 26.7°C · 107 mm rain
- Saint John’s in SeptemberAntigua and Barbuda · 359 kmHigh 28.7°C · Low 26.2°C · 127 mm rain
- Port of Spain in SeptemberTrinidad and Tobago · 374 kmHigh 29.2°C · Low 26.0°C · 101 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 Castries) is explained once on the Castries year overview and on the Sources, method and limits page.