Simpson Bay Weather in September

September in Simpson Bay brings high temperatures around 30°C (86°F) during the day, dropping to 27°C (81°F) at night, with quite a bit of rainfall expected, averaging around 134 mm (5.3 in) for the month.

Rainfall in Simpson Bay in September

Typically, about 19 days will experience rainfall, with an average of 134 mm (5.3 in) for the month. Expect frequent rainfall this month, and not just light drizzle. When it rains, it tends to come down hard.

Temperature in Simpson Bay in September

Simpson Bay in September gets highs of 30°C (86°F) during the day and drops to 27°C (81°F) at night. Conditions stay fairly consistent through the month, making it easier to plan what to wear. Nights remain warm at around 27°C (81°F). For a more comfortable sleep, a cold shower before bed and a fan or air conditioning can make a big difference.

Sunshine in Simpson Bay in September

Enjoy a sunny month with about 232 hours of sunshine, the clear skies make Simpson Bay even more beautiful.

Wind Speed in Simpson Bay in September

September has wind speeds averaging 5 m/s (10 knots). You can expect gentle to moderate winds that move small trees and make flags wave steadily on typical days. Conditions typically range from light breezes to moderate winds.

Average water temperature in September

With water at 29°C (84°F), conditions are warm and calm. Perfect for those who like tropical water temperatures, though it won't cool you down much.

September in Simpson Bay has its charm. However, if you're seeking pleasant, dry and sunny weather, our weather planner can help you explore other destinations in the world.

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For a detailed overview over the year and the best time to visit Sint Maarten, check out our Simpson Bay's climate page.

Simpson Bay Temperature in September

Min Temperature 27°C (81°F)  

Max Temperature 30°C (86°F)  

Water Temperature 29°C (84°F) *  

Chance of Rain 62%  

Precipitation 134 mm (5.3 in)  

Rainy days 19 days  

Humidity 78% *  

Windspeed 5 m/s (10 knots) *  

Sunshine 232 hours *  

Percentage Sunshine 61% *  

* Data from: Sint Maarten, Sint Maarten (3 KM, 2 Miles).

Daily Historical Temperatures

50-year average (1976-2025)

Based on our historical records, temperatures in Simpson Bay typically stay consistent throughout September, with daily highs averaging around 30°C (86°F). Nights are warm, with lows around 27°C (81°F).

Average temperatures in September

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Historical weather for Simpson Bay in September

Browse day-by-day weather records for Simpson Bay spanning 51 years. Select any month and year to see actual temperatures, rainfall, and conditions recorded on each day.

Historical weather Temperatures Precipitation

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‹ January February March April May June July August September October November December ›

Simpson Bay historical weather extremes in September

Based on 35 years of weather observations in Simpson Bay between 1990 and 2025, these are the recorded extremes.

• Simpson Bay recorded its highest September temperature of 37°C (99°F) on September 3, 1992.
• Simpson Bay experienced its chilliest September day on September 21, 2008, reaching only 27°C (81°F).
• The coldest night in September in Simpson Bay was on September 29, 2017, with a minimum of 22°C (72°F).

What to Wear in Simpson Bay in September

Warm weather calls for comfortable, breathable clothing in September. Cotton t-shirts, shorts, light dresses, and sandals are perfect. You might still want a light layer for evenings or air-conditioned places (for example buses). High rain levels are expected, so pack waterproof gear and an umbrella or poncho. The water temperature sits at about 29°C (84°F), making it perfect for swimming and water activities. Don't forget to pack your favorite swimwear and perhaps some snorkel gear. And with plenty of sunshine hours, don’t forget sunglasses, sunscreen, and maybe a sun hat.

What To Do in Simpson Bay in September

We rated the following activities from 1 (least suitable) to 10 (best) to do.

Swimming

9/10

Cycling

7/10

Walking

7/10

Camping

7/10

Outdoor sports

7/10

Select a Month

Check the conditions for any month of the year.

• January
• February
• March
• April

• May
• June
• July
• August

• September
• October
• November
• December

For a detailed overview over the year and the best time to visit Sint Maarten, check out our Simpson Bay's climate page.

More climate data for Simpson Bay

Temperature Rainfall Sunshine Humidity Wind Speed Water Temp

See the full Simpson Bay climate overview or explore weather in Sint Maarten.