Saint Lucia (Castries) weather in August
Temperature, sea and sunshine in August: long-term averages from 30 years of weather data, not a forecast.
Holiday weather in August
Good
Best time to visit: December – July
What is the weather like in Saint Lucia (Castries) in August?
In August, Saint Lucia (Castries) is hot: daytime highs average 29 °C, and even at night it stays warm at around 25 °C. The sea averages 28.8 °C – lovely and warm for swimming. The sun shines for around 9 hours a day. It is the rainy season: rain falls on about 22 days, totalling 105 mm. The air is often humid and muggy. All in all, August is a good month for a holiday in Saint Lucia (Castries).
August compared
How the weather changes from July to September. Tap a month to open it.
| JulyJul | AugustAug | SeptemberSep | |
|---|---|---|---|
| Score | 79 | 79 | 76 |
| Day | 29° | 29° | 29° |
| Night | 25° | 25° | 25° |
| Sea | 28° | 29° | 29° |
| Sun | 9 h | 9 h | 8 h |
| Rain days | 21 | 22 | 20 |
More details for August
- Daylight
- 12 h 36 min05:51 – 18:27
- UV index
- 13 · extremeclear sky, noon (estimate)All months
- Muggy days
- 31 daysdew point 18 °C or moreAll months
- Wind
- 22 km/haverage daily peakAll months
- Cloud cover
- 55 %on averageAll months
- Hot days
- 4 days30 °C or moreAll months
- Time zone
- UTC−4America/St_Lucia
How the score comes together
- Temperatureweight 35 %100 %
- Seaweight 25 %100 %
- Sunshineweight 20 %95 %
- Few rainy daysweight 20 %0 %
Each factor is rated from 0 to 100 % and weighted for the travel style “Sun, sea & sand”.
What to pack in August
- Swimwear
- Sunscreen
- Sunglasses & sun hat
- Light, breathable clothes
- Insect repellent
- Rain jacket or umbrella
Saint Lucia (Castries) in August: quick answers
Is Saint Lucia (Castries) hot in August?
Yes. In August, Saint Lucia (Castries) is hot: daytime highs average 29 °C and nights stay around 25 °C. On about 4 days the thermometer climbs to 30 °C or more.
Can you swim in Saint Lucia (Castries) in August?
Yes. In August the sea averages 28.8 °C – lovely and warm for swimming.
Does it rain much in Saint Lucia (Castries) in August?
It rains often – on about 22 days, adding up to 105 mm.
Saint Lucia (Castries) month by month
The whole year in Saint Lucia (Castries)All destinations: Saint LuciaCaribbean weather in AugustWhere to go in AugustSea temperature in August
Climate averages 1996–2025, not a forecast. Data: Copernicus ERA5 / ERA5-Land via Open-Meteo.com (CC BY 4.0), NOAA OISST, WMO 1991–2020 (NOAA NCEI), GeoNames (CC BY 4.0). Sources & licences