Gustavia (St Barts) weather in September
September in Gustavia: hot, rainy, with clean air — fine if you can take 18 rainy days.
Updated September 2026 · climate normals from ERA5 reanalysis
#11 of 12 months in Gustavia · #648 of 1413 destinations to visit in September · comfort 81/100 (tier A)
- Days
- 29°C
- Nights
- 27°C
- Wet days
- 18
- Sun
- 10.7 h
- Humidity
- 81%
- Daylight
- 12 h

Traveller notes on Gustavia in September
Notes from nearby Marigot (31 km away)
Gustavia doesn't have its own notes for September yet — these are about Marigot, close enough to share the season.
St. Martin's forum describes September as generally sunny day after day, hot and humid, with scattered 20-30 minute showers - often at night - rather than sustained rain. It's also the height of hurricane season (August through October are the most active months), so travel insurance gets recommended repeatedly. Marigot's French-side restaurant scene thins out noticeably in September as many close for the month, though posters said there's still enough open to eat well, just without the full peak-season variety - the trade-off being a genuinely quiet, uncrowded month for whatever stays open.
Other months in Gustavia
St. Barths' forum doesn't hide that October is the island's off-season for good reason - deep in hurricane season, with Gustavia turning into something close to a ghost town as most shops shutter, though core restaurants stay open. When there's no storm system nearby the weather can be genuinely lovely, but posters were honest that the opposite is possible too: one traveler reported four straight days of rain totaling over 12 inches. The trade-off multiple regulars highlighted: the lowest room rates of the year and zero crowds, for anyone willing to accept real weather risk.
Forum posters describe April as close to ideal - typically around 84F with low precipitation, and while forecasts often show rain in the mix, posters say it usually amounts to no more than about 10 minutes of actual rain on a given day. Any rain that does fall tends to be a fast-moving, widely scattered shower lasting minutes rather than a sustained downpour, with prolonged rain called genuinely rare this time of year. Posters call the good-weather run typically holding through March into April before conditions shift later in the year. For Gustavia specifically, posters describe the harbor town as St. Barth's main hub - plenty of shops and restaurants clustered around the waterfront, an easy, walkable base for exploring the rest of the island.
Add your own note from Gustavia's card on the map.
Gustavia climate normals — September
Monthly averages from ERA5 reanalysis. AQI is the mean US Air Quality Index for the month.
Crowds in Gustavia in September
How busy the place itself is — school and mass holidays, the months an editor tagged, and how sought-after the weather makes them. Never part of the comfort score.
Quietschool holidays in 2 of the markets that fill it, one of its worst months for weather(estimated)
Peak crowdsBusyShoulder seasonQuiet
Best months for Gustavia's weather
Ranked by this destination's own climate comfort score across the year — a different thing from how busy it gets (see Crowds above).
Fair weatherGustavia's weather doesn't swing hard through the year — comfort stays fairly steady in every month.
What's on in Gustavia in September
Recurring seasonal events, natural spectacles, closures and holidays — curated and sourced.
- Hazard
Atlantic hurricane season
1 Jun – 30 NovMost of the season passes without incident, but this is the island Irma flattened in September 2017 and the rebuild took years. Mid-August to mid-October is the part of the window worth insuring against. Source ↗
- Season
Autumn shutdown
1 Sep – 31 OctOff-season shutdownClosuresSeptember and October are when the villas, the hotels and most of the good restaurants close for their annual break and the staff go home. Flights still run and the beaches are empty, but plan on eating wherever is open. Source ↗
Nearby, and something's on
Within 300 km of Gustavia — a day trip or a short hop — with something on this month. Never part of the comfort score.
Where is Gustavia?
Gustavia in September — FAQ
- Is September a good time to visit Gustavia?
- September in Gustavia: hot, rainy, with clean air — fine if you can take 18 rainy days. It ranks #11 of 12 months for Gustavia on SeasonMap's comfort score (81/100).
- What is the weather like in Gustavia in September?
- In September, Gustavia averages a daily high of 28.5°C and a low of 26.9°C, with about 128.3 mm of rain over roughly 18 rainy days.
- What is the air quality in Gustavia in September?
- Gustavia has a mean US Air Quality Index of about 38 in September.
Within 300 km: Philipsburg's Sea turtle nesting around 1 Apr – 30 Nov.