# Saint Martin in September: weather

Saint Martin, Saint Martin (Caribbean). Ten-year climatology (2015-2024), not a forecast. Page: https://beaufixe.net/en/weather/stmartin/september

## Key figures

| Indicator | Value |
|---|---|
| Afternoon (mean daily max) | 27 °C |
| Night (mean daily min) | 25.2 °C |
| Sea (surface) | 29.4 °C |
| Rainy days (≥ 1 mm) | 17 / month |
| Relative humidity | 80 % |
| Probability of a 25 °C+ afternoon | 99 % |

## Month by month

| Month | Afternoon | Night | Sea | Rain (d) |
|---|---|---|---|---|
| January | 24.2 °C | 22.8 °C | 26.8 °C | 12 |
| February | 24 °C | 22.6 °C | 26.6 °C | 10 |
| March | 24 °C | 22.7 °C | 26.5 °C | 8 |
| April | 24.5 °C | 23.1 °C | 27 °C | 11 |
| May | 25.3 °C | 24 °C | 27.7 °C | 10 |
| June | 26.1 °C | 24.7 °C | 28.3 °C | 10 |
| July | 26.4 °C | 24.8 °C | 28.6 °C | 15 |
| August | 26.8 °C | 25.1 °C | 28.9 °C | 16 |
| September | 27 °C | 25.2 °C | 29.4 °C | 17 |
| October | 26.7 °C | 24.9 °C | 29.3 °C | 17 |
| November | 26 °C | 24.3 °C | 28.7 °C | 17 |
| December | 25.1 °C | 23.6 °C | 27.8 °C | 13 |

Best months : June, August, July.

## Before you go

- **Safety** : No specific restrictions. Usual precautions apply. (official advice updated 11 August 2026 — https://www.gov.uk/foreign-travel-advice/france)
- **Entry** (British passport) : No visa needed for stays of up to 90 days. Passport valid for at least 3 months. FCDO applies the France/Schengen rules here: passport issued less than 10 years before arrival; EES biometric registration may apply. (per the UK Foreign Office, 11 August 2026)
- **Vaccines** : hepatitis A and hepatitis B if you are not already vaccinated. Routine vaccines up to date (measles in particular).
- **Yellow fever** : No yellow fever locally, vaccine not recommended. Certificate required only if you arrive from a country with yellow fever risk.
- **Malaria** : None.
- **Mosquitoes** : dengue and Zika reported: protect yourself from bites.
  (per the CDC, page reviewed 25 August 2026 — https://wwwnc.cdc.gov/travel/destinations/traveler/none/saint-martin)

## Sources

Air, rain, humidity: ERA5-Land reanalysis (Copernicus) served by Open-Meteo (CC BY 4.0). Sea: NOAA OISST. Safety: FCDO (OGL v3), zones reviewed by Beau Fixe. Entry: France Diplomatie (Licence Ouverte 2.0) / FCDO. Health: CDC (public domain). Details: https://beaufixe.net/en/legal#sources

Beau Fixe — https://beaufixe.net — not a forecast; only the authorities are authoritative for safety, entry rules and health.