SeasonMapBarreirinhas (Lençóis Maranhenses) weather in September
Brazil
September in Barreirinhas: hot, dry, with clean air — a good time to visit.
#7 of 12 months in Barreirinhas · #1065 of 1383 destinations to visit in September · comfort 64/100 (tier C)
Updated September 2026 · climate normals from ERA5 reanalysis
Traveller notes on Barreirinhas in September
No notes yet. Open Barreirinhas on the map to add the first one.
Barreirinhas climate normals — September
| Daytime high | 32°C / 89°F | 🥵 hot |
|---|---|---|
| Nighttime low | 26°C / 78°F | |
| Sea temperature | 29°C / 83°F | ♨️ bath-warm |
| Rainfall | 5 mm / 0.2 in | ☀️ dry |
| Rainy days | 1 days | |
| Humidity | 72% | 💧 humid |
| Dew point | 22°C / 72°F | |
| Sunshine | 11.3 h/day | |
| Daylight | 12.1 h | |
| Wind | 24 km/h / 15 mph | |
| Air quality (US AQI) | 32 | 🍃 good |
Monthly averages from ERA5 reanalysis. AQI is the mean US Air Quality Index for the month.
Crowds in Barreirinhas 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.
BusyLagoons at their fullest, school holidays in 2 of the markets that fill it(estimated)
Peak crowdsBusyShoulder seasonQuiet
Best months for Barreirinhas'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 weatherBarreirinhas's weather peaks June–August.
Best weatherFair weatherToughest weather
What's on in Barreirinhas in September
Recurring seasonal events, natural spectacles, closures and holidays — curated and sourced.
- Nature
Lagoons at their fullest
1 Jun – 15 Sep · usuallyHigh waterCrowdedThe rains stop in May and the dune valleys hold thousands of rainwater lagoons through the southern winter. June and July are the safe months; by late September the shallow ones have gone.
Where is Barreirinhas?
Barreirinhas in September — FAQ
- Is September a good time to visit Barreirinhas?
- September in Barreirinhas: hot, dry, with clean air — a good time to visit. It ranks #7 of 12 months for Barreirinhas on SeasonMap's comfort score (64/100).
- What is the weather like in Barreirinhas in September?
- In September, Barreirinhas averages a daily high of 31.8°C and a low of 25.5°C, with about 4.7 mm of rain over roughly 1.2 rainy days.
- What is the air quality in Barreirinhas in September?
- Barreirinhas has a mean US Air Quality Index of about 32 in September.