September weather forecastWillemstad, Netherlands

September

Weather in September

The first month of the autumn, September, is still a comfortable month in Willemstad, Netherlands, with an average temperature ranging between max 19.2°C (66.6°F) and min 11.5°C (52.7°F).

Temperature

The arrival of September is marked by a minor reduction in average high-temperature, sliding from an agreeable 22.7°C (72.9°F) in August to an enjoyable 19.2°C (66.6°F). Nighttime temperatures consistently average a cool 11.5°C (52.7°F) during September.

Humidity

The average relative humidity in September is 80%.

Rainfall

In Willemstad, in September, it is raining for 7.5 days, with typically 7mm (0.28") of accumulated precipitation. Throughout the year, there are 104.9 rainfall days, and 132mm (5.2") of precipitation is accumulated.

Snowfall

April through November are months without snowfall in Willemstad.

Sea temperature

In Willemstad, the average seawater temperature in September is 18.2°C (64.8°F).
Note: Swimming is not an enjoyable activity for the majority when the water is at 18.2°C (64.8°F). The difficulty of controlling breathing increases as the temperature dips from 21°C (69.8°F) to 15°C (59°F).

Daylight

The average length of the day in September is 12h and 38min.
On the first day of September in Willemstad, sunrise is at 06:55 and sunset at 20:28. On the last day of the month, sunrise is at 07:42 and sunset at 19:21 CEST.

Sunshine

The average sunshine in September is 7.2h.

UV index

The average daily maximum UV index in September is 4. A UV Index value of 3 to 5 symbolizes a moderate threat to health from unprotected exposure to Sun's UV rays for ordinary individuals.
Note: In September, the maximum UV index of 4 suggests this advice:
Be careful. Light complexion individuals might get burns in fewer than 30 minutes. Avoiding the Sun during its peak radiation time around midday is a healthy practice. Sunglasses that guard against UVA and UVB rays are pivotal in minimizing sun-induced ocular damage.

Updated: Jan 26, 2024
Published by: Weather Atlas | About Us
Data Sources | Weather Forecasting & Climate

Frequently asked questions

Willemstad in September has an average high-temperature of 19.2°C (66.6°F) and an average low-temperature of 11.5°C (52.7°F).

In September, the average relative humidity is 80%.

In Willemstad, Netherlands, in September, during 7.5 rainfall days, 7mm (0.28") of precipitation is typically accumulated.

In Willemstad, Netherlands, snow does not fall in April through November.

In Willemstad, the average seawater temperature in September is 18.2°C (64.8°F). For most, swimming in 18.2°C (64.8°F) is not an enjoyable activity. Furthermore, controlling your breathing becomes progressively more difficult as the water temperature decreases from 21°C (69.8°F) to 15°C (59°F).

In September, the average day length is 12h and 38min.

On the first day of September in Willemstad, Netherlands, sunrise is at 06:55 and sunset at 20:28. On the last day of the month, sunrise is at 07:42 and sunset at 19:21 CEST.

In September, the average sunshine duration in Willemstad, Netherlands, is 7.2h.

In Willemstad, Netherlands, the average daily maximum UV index in September is 4. A UV Index of 3 to 5 symbolizes a moderate health threat from exposure to Sun's UV rays.

Today

Tomorrow

Long-term

Year J F M A M J J A September O N D

Aug

September

Oct

Average high temperature

22.7°C

19.2°C

14.9°C

Average low temperature

Average pressure

Average wind speed

Average max. wind speed

13km/h

12.8km/h

14.9km/h

Average wind speed gusts

Average humidity

Average rainfall

Average rainfall days

Average snowfall

Average snowfall days

Average sea temperature

Average daylight

Average sunshine

Average sunshine days

16.8

18.7

18.2

Average UV index

Average cloud cover

Average visibility

Average temperature in September
Willemstad, Netherlands

Average high temperature in September: 19.2°C

The warmest month (with the highest average high temperature) is August (22.7°C).
The month with the lowest average high temperature is January (5.3°C).

Average low temperature in September: 11.5°C

The month with the highest average low temperature is August (14.1°C).
The coldest month (with the lowest average low temperature) is February (1.4°C).

Average pressure in September
Willemstad, Netherlands

Average pressure in September: 1017.2mbar

The month with the highest atmospheric pressure is September (1017.2mbar).
The month with the lowest atmospheric pressure is November (1011.9mbar).

Average wind speed in September
Willemstad, Netherlands

Average wind speed in September: 12.2km/h

The windiest months (with the highest average wind speed) are February and December (17.5km/h).
The calmest month (with the lowest average wind speed) is August (12.1km/h).

Average humidity in September
Willemstad, Netherlands

Average humidity in September: 80%

The month with the highest relative humidity is December (87%).
The month with the lowest relative humidity is April (74%).

Average rainfall in September
Willemstad, Netherlands

Average rainfall in September: 7mm

The wettest month (with the highest rainfall) is June (15mm).
The driest month (with the least rainfall) is April (5mm).

Average rainfall days in September
Willemstad, Netherlands

Average rainfall days in September: 7.5 days

The month with the highest number of rainy days is August (10.3 days).
The month with the least rainy days is April (6.3 days).

Average snowfall in September
Willemstad, Netherlands

Average snowfall in September: 0mm

The month with the highest snowfall is February (10mm).
The months with the least snowfall are April, May, June, July, August, September, October and November (0mm).

Average snowfall days in September
Willemstad, Netherlands

Average snowfall days in September: 0 days

The month with the highest number of snowfall days is February (2.3 days).
The months with the least snowfall days are May, June, July, August, September and October (0 days).

Average sea temperature in September
Willemstad, Netherlands

Average sea temperature in September: 18.2°C

The best month for swimming (with the highest average sea temperature) is August (18.3°C).
The coldest months (with the lowest average sea temperature) are February and March (6.6°C).

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

Average daylight in September: 12h and 36min

The month with the longest days is June (Average daylight: 16h and 36min).
The month with the shortest days is December (Average daylight: 7h and 54min).

Average sunshine in September: 7h and 12min

The month with the most sunshine is June (Average sunshine: 9h and 12min).
The month with the least sunshine is December (Average sunshine: 3h and 24min).

Average sunshine days in September
Willemstad, Netherlands

Average sunshine days in September: 18.7 days

The month with the most sunshine days is April (21.3 days).
The month with the least sunshine days is November (15.5 days).

Average UV index in September
Willemstad, Netherlands

Average UV index in September: 4

The months with the highest UV index are June, July and August (UV index 5).
The months with the lowest UV index are January, February, November and December (UV index 2).

Average cloud cover in September
Willemstad, Netherlands

Average cloud cover in September: 47

The month with the most cloud cover is December (Cloud cover 66).
The month with the least cloud cover is April (Cloud cover 42).

Average visibility in September
Willemstad, Netherlands

Average visibility in September: 9km

The months with the highest visibility are January, February, March, April, May, June, July, August, September, October, November and December (9km).
The months with the lowest visibility are January, February, March, April, May, June, July, August, September, October, November and December (9km).