São Luís in September
In September, São Luís averages 32°C (89°F) during the day and 25°C (78°F) at night, with frequent rain — about 25 days of the month see precipitation (29 mm total).
ShoulderConditions are warm and beach-friendly. Expect daily rain or showers, often in heavy bursts.
September is one of the wetter and less comfortable months in São Luís. If your dates are flexible, consider a different time of year.
How September compares to the rest of the year in São Luís
September is one of the warmest months in São Luís (2nd of 12) and one of the driest months (10th of 12). Daytime temperature runs 1°C above the annual average (30°C). September runs 1°C warmer than August (31°C) and stays flat into October.
September sunrise & sunset in São Luís
Times shown for São Luís local time (America/Fortaleza), calculated for the 15th of September. They shift by a few minutes day to day across the month.
Photography light in São Luís — September
Golden-hour and blue-hour windows for the 15th of September, in São Luís's local time. Use these for soft warm light (golden) or cool architectural twilight (blue).
📅 When to book — São Luís 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 (Shoulder) and São Luís's popularity.
Crowds & pricing — September in São Luís
São Luís is in a shoulder season month — fewer crowds, slightly lower prices, and a calmer atmosphere than peak weeks. Most major sights stay open with normal hours, though a handful of seasonal restaurants or boat trips may run reduced schedules. Many regulars consider these months the best time to visit because you trade a small amount of weather reliability for a much more pleasant on-the-ground experience.
Sun & mosquito risk — September in São Luís
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.
São Luís in other months
| Month | Avg high | Avg low | Rainfall | Rain days | Snow days |
|---|---|---|---|---|---|
| January | 30°C / 85°F | 25°C / 76°F | 238 mm | 30 | — |
| February | 29°C / 84°F | 24°C / 76°F | 327 mm | 28 | — |
| March | 29°C / 84°F | 24°C / 75°F | 473 mm | 31 | — |
| April | 29°C / 85°F | 24°C / 76°F | 370 mm | 30 | — |
| May | 30°C / 85°F | 24°C / 76°F | 249 mm | 31 | — |
| June | 30°C / 85°F | 24°C / 76°F | 126 mm | 29 | — |
| July | 30°C / 86°F | 24°C / 76°F | 74 mm | 29 | — |
| August | 31°C / 88°F | 25°C / 77°F | 39 mm | 27 | — |
| September | 32°C / 89°F | 25°C / 78°F | 29 mm | 25 | — |
| October | 32°C / 89°F | 26°C / 78°F | 33 mm | 23 | — |
| November | 32°C / 89°F | 26°C / 78°F | 73 mm | 22 | — |
| December | 31°C / 88°F | 26°C / 78°F | 117 mm | 26 | — |
Other cities with similar September weather
🌍 See the full ranked list of climate twins for São Luís in September →
Frequently asked questions
How hot is São Luís in September?
In September, São Luís averages a high of 32°C (89°F) and a low of 25°C (78°F) — generally hot.
Does it rain a lot in São Luís in September?
September is quite rainy in São Luís, with about 25 rainy days on average.
Is September a good time to visit São Luís?
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 São Luís in September?
Pack lightweight, breathable clothing, sunglasses and sunscreen, plus a compact umbrella or rain jacket. See the full September packing list for São Luís for a complete, climate-based checklist.
Check the live 10-day forecast and sunrise/sunset.