Willemstad
Curaçao
Long-term weather forecast
Long-term weather forecast

September weather forecast and climate
Willemstad, Curaçao

The organized harbor city of Willemstad in Curaçao, with two small ships at the docks
The organized harbor city of Willemstad in Curaçao, with two small ships at the docks
September, the first month of the autumn, in Willemstad, is also a hot month, with temperature in the range of an average high of 32.6°C (90.7°F) and an average low of 26.5°C (79.7°F).
The ideal sea water temperature of 29°C (84.2°F) and only 4.6 rainfall days, with 48.6mm (1.9") of accumulated rainfall, make September the best time for swimming and other water activities.

Temperature

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

Heat index

The average heat index in September is calculated to 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. Exposure to direct sunshine can increase heat index values by up to 15 Fahrenheit (8 Celsius) degrees.
Note: The heat index, also known as 'real feel', 'feels like', 'apparent temperature', or 'felt air temperature', is a measure of how hot it feels when the actual air humidity is factored in. This effect is subjective, depending on the activity and individual's heat perception influenced by various reasons (pregnancy, metabolic differences, clothing). Bear in mind that direct sunshine exposure increases weather impact, and may raise heat index by up to 15 Fahrenheit (8 Celsius) degrees. Heat index values are particularly important for children. Young children are generally more endangered than adults, as they usually less sweat. And also, due to larger skin surface relative to their small bodies and higher heat production as a result of their activity.
Perspiration is the human body's physiological response to high temperatures and is an attempt to lower body temperature through evaporation of sweat. High relative humidity reduces the evaporation rate, resulting in a lower heat removal rate from the body, causing the perception of being overheated. If the body can not disperse the excessive heat and body temperature reaches conditions of hyperthermia, above 37.5°C (99.5°F) to 38.3°C (100.9°F), thermal conditions are potentially life-threatening.

Humidity

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

Rainfall

In September, in Willemstad, the rain falls for 4.6 days. Throughout September, 48.6mm (1.9") of precipitation is accumulated. Throughout the year, there are 69.4 rainfall days, and 553.4mm (21.8") 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 12.2h.

Sunshine

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

UV index

Months with the highest UV index are February through September, with an average maximum UV index of 12. A UV Index value of 11, and more, symbolizes an extreme threat to health from the exposure to the Sun's UV radiation for the average person.
Note: In September, the average maximum UV index of 12 translate into the following recommendations:
Practice all-important precautions. Light skin people may get burned in less than 5 minutes. The Sun's UV radiation is most powerful between 10 a.m. and 4 p.m. To the extent possible, limit exposure to the direct sun during these hours. A wide-brim hat offers excellent sun protection for eyes, ears, face, and neck. Sunglasses with UVA and UVB protection significantly reduce eye damage from sun exposure. Tightly woven, loose-fitting clothes provide additional protection from the Sun. 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.

What is the warmest month in Willemstad?

September is the warmest month in Willemstad, Curaçao, 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, 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. 'feels like', 'felt air temperature'), that combines both air temperature and relative humidity, 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 Willemstad, during September, the rain falls for 4.6 days and regularly aggregates up to 48.6mm (1.9") of precipitation.

When is the sea warmest in Willemstad?

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

What is the sea water temperature in September in Willemstad?

In September, the average sea temperature in Willemstad, Curaçao, 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.

How many hours of daylight does Willemstad have in September?

The average length of the day in September in Willemstad, Curaçao, is 12.2h.

How many hours of sunshine does Willemstad have in September?

The average sunshine in September in Willemstad, Curaçao, is 8.6h.

When is the highest UV index in Willemstad?

Months with the highest UV index are February through September, with an average maximum UV index of 12.

What is the UV index reading in September in Willemstad?

The average daily maximum UV index in September in Willemstad, Curaçao, is 12. A UV Index of 11, and more, symbolizes an extreme health vulnerability from the exposure to the Sun's UV rays.
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).

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%).

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 lowest rainfall) is March (14.2mm).

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 lowest number of rainy days is May (2 days).

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

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

Average daylight in September / Average sunshine in September - Willemstad, Curaçao
  • Average daylight in September: 12.2h

Months with the longest days are June and July (Average daylight: 12.8h).
The month with shortest days is December (Average daylight: 11.4h).

  • Average sunshine in September: 8.6h

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

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

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).