- Book online with TUI & save up to 7% on holidays
- FREE child places available for select holidays
- Pay £0 deposits with direct debit & spread the cost
St Lucia weather in September 2025
Expect 30°C daytime maximum temperatures in the shade with on average 8 hours of sunshine per day in St Lucia in September. Check more long-term weather averages for St Lucia in September before you book your next holiday to St Lucia in 2025/2026.
- 30°C max day temperature
30 - 8 hours of sunshine per day
- 25 days with some rainfall
25 - 24°C min night temperature
24 - 12 hours of daylight per day
12 - Very High heat & humidity
VH - 224 mm of monthly rainfall
224 - 11+ (Extreme) UV index
11 - 29°C sea temperature
29
More about St Lucia
- Overview
- Best time to visit
- Weather by month
- 5-day weather forecast
- Destinations
- Travel advice
- Deals & discounts
St Lucia by month
Jan Feb Mar Apr May Jun Jul Aug Sep Oct Nov Dec
Recommended for St Lucia
TUI deal finder
The September weather guide for St Lucia (Castries) shows long term weather averages processed from data supplied by CRU (University of East Anglia), the Met Office & the Netherlands Meteorological Institute. Find out more about our data sources.
Top St Lucia destinations
Below are average maximum temperatures at popular countries, regions and places in St Lucia in September. Select a holiday destination to see more weather parameters.
All St Lucia destinations
- Anse la Raye
- Cap Estate
- Castries
- Choc Bay
- Grand Anse
- Gros Islet
- Marigot Bay
- Morgan Bay
- Reduit Beach
- Rodney Bay
- Soufriere
- Vieux Fort
Metric (°C / mm) | Imperial (°F / inches)
More about St Lucia
How hot is it in St Lucia in September?
Daytime temperatures usually reach 30°C in Castries, St Lucia in September with very high heat and humidity, falling to 24°C at night.
How sunny is it in St Lucia in September?
There are normally 8 hours of bright sunshine each day in Castries, St Lucia in September - that's 62% of daylight hours.
How warm is the sea around St Lucia in September?
The average sea temperature around Castries, St Lucia in September is 29°C.
Does it rain in St Lucia in September?
There are usually 25 days with some rain in Castries, St Lucia in September and the average monthly rainfall is 224mm.
What is the chance of a hurricane in St Lucia in September?
On average 1.1 days in September in Castries, St Lucia are likely to be affected by the passage of one or more tropical storms.
St Lucia September sunrise & sunset times
Browse the sunrise and sunset times for St Lucia in September 2025. Select a month to view St Lucia sunrise and sunset times for the next 12 months. The St Lucia sunrise and sunset times shown below are for Castries.
JanFebMarAprMayJunJulAugSepOctNovDec
| Date | Sunrise times | Sunset times |
|---|---|---|
| Monday, 1st September 2025 | 05:52 | 18:15 |
| Monday, 15th September 2025 | 05:53 | 18:05 |
| Tuesday, 30th September 2025 | 05:54 | 17:54 |
Be inspired
Get your weekly fix of holiday inspiration from some of the world's best travel writers plus save on your next trip with the latest exclusive offers
We promise not to share your details
Related posts
Popular travel offers
Explore holidays in the sun for less
- Beach holidays
- Family holidays
- City breaks
- Summer holidays
- Winter sun holidays
- Holiday offers
- Top travel brands
- Airlines & flights
- Discount hotels
- Airport parking deals
- TUI
- Jet2holidays
- easyJet holidays
- Love Holidays
- Black Friday sales
Airport parking
- Manchester Airport
- Stansted Airport
- Bristol Airport
- Luton Airport
- Birmingham Airport
- Edinburgh Airport
- Gatwick Airport
- Glasgow Airport
- Newcastle Airport
Airport lounges
- Manchester Airport
- Birmingham Airport
- Bristol Airport
- Edinburgh Airport
- Glasgow Airport
- Heathrow Airport
- Newcastle Airport
- Stansted Airport
- Gatwick Airport