September weather forecast
Willemstad, Curaçao

The organized harbor city of Willemstad in Curaçao
The organized harbor city of Willemstad in Curaçao

Weather in September

The first month of the autumn, September, is still a hot month in Willemstad, Curaçao, with an average temperature ranging between min 26.5°C (79.7°F) and max 32.6°C (90.7°F).
The ideal sea water temperature of 29°C (84.2°F) and only 4.6 rainfall days, with 48.6mm (1.91") of accumulated rainfall, makes September the best time for swimming and other water activities.

Temperature

The warmest month is September, with an average high-temperature of 32.6°C (90.7°F) and an average low-temperature of 26.5°C (79.7°F).

Heat index

In September, the average heat index is evaluated at a life-threatening hot 45.4°C (113.7°F). Beware: Heat cramps and heat exhaustion are very likely. Heatstroke is imminent with prolonged activity.
Note that heat index values are valued for light wind and location in the shade. With exposure to direct sunlight, the heat index may be increased by up to 15 Fahrenheit (8 Celsius) degrees.
Note: The heat index, also known as 'apparent temperature', 'felt air temperature', 'real feel', or 'feels like', is a measure that combines air temperature and relative humidity into a single value that indicates how hot the weather feels. This effect is subjective, depending on the activity and individual's heat perception influenced by various reasons (differences in body mass, height, and shape, clothing, wind). Be aware that direct exposure to sunlight increases heat impact and may raise the heat index by up to 15 Fahrenheit (8 Celsius) degrees. Heat index values are particularly important for children. Children are often less aware of the need to rest and re-hydrate. Thirst is a late sign of dehydration - it is vital to remain hydrated, particularly during prolonged physical activities.
The human body normally cools itself by perspiration. Excessive warmth is eliminated from the body by evaporation of sweat. Under high air temperature and humidity (high heat index) conditions, perspiration is limited, and the perception of heat is increased. When heat gain surpasses the level the body can shed, body temperature begins to increase, and consequently, overheating and dehydration can occur, with varying severity.

Humidity

The average relative humidity in September is 77.5%.

Rainfall

In Willemstad, Curaçao, during September, the rain falls for 4.6 days and regularly aggregates up to 48.6mm (1.91") of precipitation. Throughout the year, in Willemstad, there are 69.4 rainfall days, and 553.4mm (21.79") of precipitation is accumulated.

Sea temperature

September and October, with an average sea temperature of 29°C (84.2°F), are months with the warmest seawater.
Note: For any water activity, surface water temperatures between 25°C (77°F) and 29°C (84.2°F) are considered as excellent and extremely pleasant for lengthened periods.

Daylight

In September, the average length of the day is 12h and 11min.
On the first day of the month, sunrise is at 06:24 and sunset at 18:45. On the last day of September, sunrise is at 06:24 and sunset at 18:26 AST.

Sunshine

In September, the average sunshine is 8.6h.

UV index

February through September, with an average maximum UV index of 12, are months with the highest UV index. A UV Index estimate of 11, and higher, represents an extreme threat to health from unprotected exposure to Sun's UV rays for the ordinary person.
Note: In September, the average maximum UV index of 12 translate into the following recommendations:
Take all necessary precautions, as unprotected skin can burn in minutes. Seek shade and minimize exposure to direct Sun in a period between 10 a.m. and 4 p.m. when UV radiation is most intense; keep in mind that shade structures like parasols or canopies do not provide perfect sun protection. On bright days sunglasses that block both UVA and UVB rays should be worn. A hat with a wide brim is extremely helpful, as it can prevent roughly 50% of UV radiation from reaching the eyes. Even on cloudy days, a sunscreen with a minimum 30 sun protection factor should be generously applied and frequently re-applied, including after every swim or outdoor exercise. Caution! The reflection of sand and water significantly increases the intensity of the Sun's UV radiation.
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FAQ

What is the warmest month in Willemstad?

The warmest month in Willemstad is September, with an average high-temperature of 32.6°C (90.7°F) and an average low-temperature of 26.5°C (79.7°F).

What is the temperature in September in Willemstad?

The average high-temperature, in September, in Willemstad, Curaçao, is 32.6°C (90.7°F), while the average low-temperature is 26.5°C (79.7°F). In September, the average heat index (a.k.a. 'felt air temperature', 'feels like'), which takes the relative humidity and factors it into the air temperature reading, is evaluated at 45.4°C (113.7°F).

What is the average humidity in September in Willemstad?

In Willemstad, the average relative humidity in September is 77.5%.

How many days does it rain in September in Willemstad?

In September, in Willemstad, the rain falls for 4.6 days. Throughout September, 48.6mm (1.91") of precipitation is accumulated.

What are the months with the warmest sea water in Willemstad?

September and October, with an average sea temperature of 29°C (84.2°F), are months with the warmest seawater in Willemstad, Curaçao.

How warm is the water in September in Willemstad?

In Willemstad, Curaçao, the average seawater temperature in September is 29°C (84.2°F). For any water activity, surface water temperatures between 25°C (77°F) and 29°C (84.2°F) are considered as excellent and extremely pleasant for lengthened periods.

What is the average length of the day in September in Willemstad?

The average day length in September in Willemstad is 12h and 11min.

What time are sunrise and sunset in September in Willemstad?

In September, on the first day of the month, sunrise is at 06:24 and sunset at 18:45. On the last day of the month, sunrise is at 06:24 and sunset at 18:26 AST.

How many hours of sunshine does Willemstad have in September?

In Willemstad, Curaçao, the average sunshine duration in September is 8.6h.

What is the month with the highest UV index in Willemstad?

The months with the highest UV index in Willemstad, Curaçao, are February through September, with an average maximum UV index of 12.

What is the UV index intensity in September in Willemstad?

The average daily maximum UV index in September in Willemstad is 12. A UV Index value of 11, and more, symbolizes an extreme health vulnerability from unprotected exposure to UV radiation.

Average temperature in September
Willemstad, Curaçao

Average temperature in September - Willemstad, Curaçao
  • Average high temperature in September: 32.6°C

The warmest month (with the highest average high temperature) is September (32.6°C).
The month with the lowest average high temperature is January (29.7°C).

  • Average low temperature in September: 26.5°C

The month with the highest average low temperature is September (26.5°C).
The coldest month (with the lowest average low temperature) is January (24.3°C).

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Average humidity in September
Willemstad, Curaçao

Average humidity in September - Willemstad, Curaçao
  • Average humidity in September: 77.5%

The month with the highest relative humidity is November (79.6%).
The month with the lowest relative humidity is March (76.1%).

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Average rainfall in September
Willemstad, Curaçao

Average rainfall in September - Willemstad, Curaçao
  • Average rainfall in September: 48.6mm

The wettest month (with the highest rainfall) is December (99.8mm).
The driest month (with the least rainfall) is March (14.2mm).

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Average rainfall days in September
Willemstad, Curaçao

Average rainfall days in September - Willemstad, Curaçao
  • Average rainfall days in September: 4.6 days

The month with the highest number of rainy days is December (11.5 days).
The month with the least rainy days is May (2 days).

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Average sea temperature in September
Willemstad, Curaçao

Average sea temperature in September - Willemstad, Curaçao
  • Average sea temperature in September: 29°C

The best months for swimming (with the highest average sea temperature) are September and October (29°C).
The coldest months (with the lowest average sea temperature) are February and March (26°C).

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Average daylight in September /
Average sunshine in September
Willemstad, Curaçao

Average daylight in September / Average sunshine in September - Willemstad, Curaçao
  • Average daylight in September: 12h and 11min

The month with the longest days is June (Average daylight: 12h and 50min).
The month with the shortest days is December (Average daylight: 11h and 26min).

  • Average sunshine in September: 8.6h

The month with the most sunshine is August (Average sunshine: 9.5h).
The month with the least sunshine is December (Average sunshine: 7.8h).

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Average UV index in September
Willemstad, Curaçao

Average UV index in September - Willemstad, Curaçao
  • Average UV index in September: 12

The months with the highest UV index are February, March, April, May, June, July, August and September (UV index 12).
The month with the lowest UV index is December (UV index 9).

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