September · Saint Lucia
Best time to visit Castries in September Weather, crowds & prices
Weather in Castries in September
Average temperature 30°C, 73 mm of rain, about 27 days with 6+ hours of sunshine and 77% humidity — based on the five most recent complete years of ERA5 data (2021–2025).
September score
8.9/10
Ranked #10 of 12 months
- Avg temp
- 30°C
- Rainfall
- 73 mm
- Humidity
- 77%
- Days with 6h+ sun
- 27
- Crowd Density
- Quiet / Uncrowded
- Average Expenses
- $ · Budget Friendly ($)
September in Castries scores 8.9/10 for beach and coastal travel - ranked #10 of 12. Expect around 30°C, 73 mm of rain, and roughly 27 days with 6+ hours of sunshine this month.
Castries is Saint Lucia's capital, a harbour town beneath green hills on the island's northwest coast.
September is one of the strongest months in Castries (10th)
September averages 30°C (85°F) and humidity near 77%, so the practical pattern is early mornings, a long midday break, and evenings back outside.
Rainfall runs 73 mm, so plan one flexible day in three; you still get about 27 days with 6+ hours of sunshine and 12.1 hours of daylight.
A 8.9/10 puts this among the year's best months in Castries (10th of 12); only March scores higher, at 9.8/10.
Pack the lightest breathable clothing you own, a hat, and more water than feels necessary, a packable rain layer.
Figure on low-season pricing, with crowds are light for this destination.
Frequently asked
- What is the weather like in Castries in September?
- In September, Castries averages 30°C, 73 mm of rain, and about 27 days with 6+ hours of sunshine. Its climate-comfort score is 8.9/10.
- Is September a good time to visit Castries?
- September earns a 8.9/10 climate-comfort score. Use the year-round chart to weigh the weather against your budget and crowd preferences.
- How much does it rain in Castries in September?
- Expect about 73 mm of rain in September. Average humidity is 77% and there are about 27 days with 6+ hours of sunshine.
Curated in Castries
Tickets & experiences
Things to do in Castries
Castries, Saint Lucia. Live activities and tours from GetYourGuide, matched to this destination.