Castries weather in September
September in Castries: sweltering, rainy, with clean air — an excellent time to visit.
#7 of 12 months in Castries · #192 of 604 destinations to visit in September · comfort 85/100 (tier A)
Updated June 2026 · climate normals from ERA5 reanalysis
Castries climate normals — September
| Daytime high | 30°C / 86°F | 🔥 sweltering |
|---|---|---|
| Nighttime low | 26°C / 78°F | |
| Feels like (high) | 35°C / 95°F | |
| Rainfall | 88 mm / 3.5 in | 🌧 rainy |
| Rainy days | 19 days | |
| Humidity | 77% | 💦 very humid |
| Dew point | 23°C / 74°F | |
| Sunshine | 11 h/day | |
| Daylight | 12.2 h | |
| Wind | 18 km/h / 11 mph | |
| Air quality (US AQI) | 32 | 🍃 good |
Monthly averages from ERA5 reanalysis. AQI is the mean US Air Quality Index for the month.
Where is Castries?
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Castries in September — FAQ
- Is September a good time to visit Castries?
- September in Castries: sweltering, rainy, with clean air — an excellent time to visit. It ranks #7 of 12 months for Castries on SeasonMap's comfort score (85/100).
- What is the weather like in Castries in September?
- In September, Castries averages a daily high of 30°C and a low of 25.8°C, with about 87.8 mm of rain over roughly 18.6 rainy days.
- What is the air quality in Castries in September?
- Castries has a mean US Air Quality Index of about 32 in September.