Hot in Sep
31°C average high
avg high · 19° at night
25°C+ on almost every day
Caribbean
St Lucia weather in September
Is it warm? Yes. September in St Lucia is hot: afternoons average 29°C and nights 24°C. Most days (80%) peak between 28°C and 31°C.
Hot · average high
29°C
25°C or more on almost every day.
- Average low24°overnight
- Sea30°average, 2023–2025
- Rainy days1396 mm in the month
- SkyOften cloudy60% cloud · 17% clear days
How warm it really gets
Every September afternoon from 2011–2025: 450 days. Most (80%) peaked between 28° and 31°.
September, year by year
The average September high in each year. The warmest, 2023, averaged 31°C; the coolest, 2014, 28°C.
Compared with home
Average September highs. Expect rain on about 13 days (96 mm in a typical month).
- St Lucia29°
- London19°
- Manchester17°
- Dublin17°
- Cork17°
- Belfast16°
- Glasgow16°
Warmer in September, not much further
Flying times are estimates from Dublin; St Lucia is about 8h 30m.
Hot in Sep
33°C average high
avg high · 18° at night
25°C+ on almost every day · often 35°C+
Hot in Sep
32°C average high
avg high · 20° at night
25°C+ on almost every day
Air: ERA5 reanalysis via Open-Meteo, 2011–2025. Sea: Copernicus Marine analysis via Open-Meteo, 2023–2025. Rainy day = 2 mm or more. Clear day = average cloud cover of 30% or less. These are averages of past weather, not a forecast. Methodology