St. Lucia (Castries) in September
In September, St. Lucia (Castries) averages 30°C (86°F) during the day and 26°C (78°F) at night, with frequent rain — about 27 days of the month see precipitation (115 mm total).
Off-peakConditions are warm and beach-friendly. Expect daily rain or showers, often in heavy bursts.
It's peak hurricane season in St. Lucia (Castries) during September. Travel is possible but expect storm risk, possible flight disruption, and generally lower travel insurance coverage.
How September compares to the rest of the year in St. Lucia (Castries)
September is one of the warmest months in St. Lucia (Castries) (1st of 12) and moderately rainy compared to the rest of the year (6th of 12). Daytime temperature runs 1°C above the annual average (29°C). September runs 1°C warmer than August (29°C) and cools 1°C in October (29°C).
September sunrise & sunset in St. Lucia (Castries)
Times shown for St. Lucia (Castries) local time (America/St_Lucia), calculated for the 15th of September. They shift by a few minutes day to day across the month.
Photography light in St. Lucia (Castries) — September
Golden-hour and blue-hour windows for the 15th of September, in St. Lucia (Castries)'s local time. Use these for soft warm light (golden) or cool architectural twilight (blue).
📅 When to book — St. Lucia (Castries) in September
Travel writers usually only tell you when to go. Here's when to book flights and lodging for the best mix of price and availability, based on September's tier (Off-peak) and St. Lucia (Castries)'s popularity.
Crowds & pricing — September in St. Lucia (Castries)
This is off-peak for St. Lucia (Castries) — the lowest prices of the year and the fewest crowds, but with real trade-offs: some restaurants, hotels, and beach businesses may close for the season; weather conditions can make outdoor activities unpredictable; and a handful of seasonal sights run reduced hours or close entirely. Great if you prefer a quiet local rhythm and don't mind the climate giving you reasons to choose indoor activities.
Why this tier: peak hazard season (1 active)
Sun & mosquito risk — September in St. Lucia (Castries)
UV is a clear-sky sea-level estimate — clouds, altitude, and reflective surfaces (snow, water) shift it ±30%. Mosquito risk is climate-derived only; for current disease advisories (dengue, malaria, zika) check the CDC or WHO travel pages before your trip.
Sea temperature in St. Lucia (Castries) — September
Across the year St. Lucia (Castries)'s sea swings from 27.1°C (February) to 30.3°C (September) — September sits at 30.3°C.
St. Lucia (Castries) in other months
| Month | Avg high | Avg low | Rainfall | Rain days | Snow days |
|---|---|---|---|---|---|
| January | 27°C / 81°F | 24°C / 75°F | 56 mm | 26 | — |
| February | 27°C / 81°F | 24°C / 74°F | 47 mm | 24 | — |
| March | 28°C / 82°F | 24°C / 75°F | 50 mm | 26 | — |
| April | 29°C / 83°F | 24°C / 76°F | 40 mm | 23 | — |
| May | 29°C / 85°F | 25°C / 77°F | 53 mm | 26 | — |
| June | 29°C / 85°F | 25°C / 78°F | 96 mm | 27 | — |
| July | 29°C / 84°F | 25°C / 78°F | 112 mm | 29 | — |
| August | 29°C / 85°F | 26°C / 78°F | 114 mm | 29 | — |
| September | 30°C / 86°F | 26°C / 78°F | 115 mm | 27 | — |
| October | 29°C / 85°F | 26°C / 78°F | 108 mm | 28 | — |
| November | 28°C / 83°F | 25°C / 77°F | 114 mm | 28 | — |
| December | 28°C / 82°F | 25°C / 76°F | 60 mm | 23 | — |
Other cities with similar September weather
🌍 See the full ranked list of climate twins for St. Lucia (Castries) in September →
Frequently asked questions
How hot is St. Lucia (Castries) in September?
In September, St. Lucia (Castries) averages a high of 30°C (86°F) and a low of 26°C (78°F) — generally hot.
Does it rain a lot in St. Lucia (Castries) in September?
September is quite rainy in St. Lucia (Castries), with about 27 rainy days on average.
Is September a good time to visit St. Lucia (Castries)?
September is hot but on the rainy side. It suits travelers who are comfortable with hot weather; check the month-by-month ranking to compare it against the rest of the year.
What should I pack for St. Lucia (Castries) in September?
Pack lightweight, breathable clothing, sunglasses and sunscreen, plus a compact umbrella or rain jacket. See the full September packing list for St. Lucia (Castries) for a complete, climate-based checklist.
Check the live 10-day forecast and sunrise/sunset.