September weather forecast
Alajuela, Costa Rica

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Weather in September

September, in Alajuela, Costa Rica, experiences daily high and low temperatures similar to the earlier months, while embracing other changes in weather parameters. Daylight hours are on a gradual decline while the cloud cover is denser resulting in fewer sunshine hours. Rainfall of 321mm (12.64") over approximately 29.3 days and a slight reduction in visibility are typical of the continued wet season. Additionally, a drop in average wind speed reflects the calmness of this month in terms of wind activity. The UV index maintains its previous score, marking consistency in this parameter.

Temperature

The onset of September manifests an average high-temperature of a still moderately hot 24.5°C (76.1°F), demonstrating a minor variation from the preceding month. Throughout September, an average low-temperature of 17.5°C (63.5°F) is expected.

Humidity

In Alajuela, the average relative humidity in September is 89%.

Rainfall

In Alajuela, in September, it is raining for 29.3 days, with typically 321mm (12.64") of accumulated precipitation. Throughout the year, there are 289.5 rainfall days, and 2506mm (98.66") of precipitation is accumulated.

Daylight

In September, the average length of the day is 12h and 11min.
On the first day of the month, sunrise is at 05:28 and sunset at 17:46. On the last day of September, in Alajuela, sunrise is at 05:26 and sunset at 17:28 CST.

Sunshine

In September, the average sunshine in Alajuela is 7h.

UV index

January, February, May through December, with an average maximum UV index of 5, are months with the lowest UV index in Alajuela. A UV Index estimate of 3 to 5 represents a medium health hazard from exposure to the Sun's UV rays for the average person.
Note: The maximum daily UV index, 5 in September, converts into the following recommendations:
Take care. Persons with lighter skin might suffer burns in less than 30 minutes. Midday is when the Sun's radiation is strongest; avoid prolonged exposure during this time. In bright sunlight, prioritize sunglasses that grant protection from UVA and UVB radiation.
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Frequently asked questions

What is the usual temperature for Alajuela in September?

In September, in Alajuela, the average high-temperature is 24.5°C (76.1°F), and the average low-temperature is 17.5°C (63.5°F). The average heat index (a.k.a. 'apparent temperature', 'feels like'), which combines air temperature and relative humidity, in April is estimated at 31°C (87.8°F).

What is the average humidity in September in Alajuela?

In September, the average relative humidity in Alajuela is 89%.

How much does it rain in Alajuela in September?

In Alajuela, Costa Rica, in September, it is raining for 29.3 days, with typically 321mm (12.64") of accumulated precipitation.

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

In September, the average day length in Alajuela, Costa Rica, is 12h and 11min.

What time are sunrise and sunset in September in Alajuela?

On the first day of September in Alajuela, sunrise is at 05:28 and sunset at 17:46. On the last day of the month, sunrise is at 05:26 and sunset at 17:28 CST.

How long on average sun shines in September in Alajuela?

The average sunshine duration in September in Alajuela, Costa Rica, is 7h.

When is the lowest UV index in Alajuela?

January, February, May through December, with an average maximum UV index of 5, are months with the lowest UV index.

What is the UV index reading in September in Alajuela?

In Alajuela, the average daily maximum UV index in September is 5. A UV Index value of 3 to 5 symbolizes a medium health risk from unsafe exposure to Sun's UV rays.

Average temperature in September
Alajuela, Costa Rica

Average temperature in September - Alajuela, Costa Rica
  • Average high temperature in September: 24.5°C

The warmest month (with the highest average high temperature) is April (28°C).
The month with the lowest average high temperature is October (23.8°C).

  • Average low temperature in September: 17.5°C

The month with the highest average low temperature is May (18.3°C).
The coldest month (with the lowest average low temperature) is January (15.2°C).

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Average pressure in September
Alajuela, Costa Rica

Average pressure in September - Alajuela, Costa Rica
  • Average pressure in September: 1011mbar

The month with the highest atmospheric pressure is January (1012.2mbar).
The month with the lowest atmospheric pressure is October (1010.8mbar).

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Average wind speed in September
Alajuela, Costa Rica

Average wind speed in September - Alajuela, Costa Rica
  • Average wind speed in September: 3.9km/h

The windiest month (with the highest average wind speed) is February (10.9km/h).
The calmest month (with the lowest average wind speed) is September (3.9km/h).

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Average humidity in September
Alajuela, Costa Rica

Average humidity in September - Alajuela, Costa Rica
  • Average humidity in September: 89%

The month with the highest relative humidity is October (90%).
The month with the lowest relative humidity is March (71%).

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Average rainfall in September
Alajuela, Costa Rica

Average rainfall in September - Alajuela, Costa Rica
  • Average rainfall in September: 321mm

The wettest month (with the highest rainfall) is October (421mm).
The driest month (with the least rainfall) is February (25mm).

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Average rainfall days in September
Alajuela, Costa Rica

Average rainfall days in September - Alajuela, Costa Rica
  • Average rainfall days in September: 29.3 days

The month with the highest number of rainy days is October (30.5 days).
The month with the least rainy days is February (12.3 days).

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Average daylight in September /
Average sunshine in September
Alajuela, Costa Rica

Average daylight in September / Average sunshine in September - Alajuela, Costa Rica
  • Average daylight in September: 12h and 1min

The month with the longest days is June (Average daylight: 12h and 42min).
The month with the shortest days is December (Average daylight: 11h and 30min).

  • Average sunshine in September: 7h and 0min

The month with the most sunshine is February (Average sunshine: 9h and 24min).
The month with the least sunshine is October (Average sunshine: 6h and 12min).

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Average sunshine days in September
Alajuela, Costa Rica

Average sunshine days in September - Alajuela, Costa Rica
  • Average sunshine days in September: 0.4 days

The month with the most sunshine days is February (11.9 days).
The month with the least sunshine days is September (0.4 days).

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Average UV index in September
Alajuela, Costa Rica

Average UV index in September - Alajuela, Costa Rica
  • Average UV index in September: 5

The months with the highest UV index are March and April (UV index 6).
The months with the lowest UV index are January, February, May, June, July, August, September, October, November and December (UV index 5).

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Average cloud cover in September
Alajuela, Costa Rica

Average cloud cover in September - Alajuela, Costa Rica
  • Average cloud cover in September: 59

The month with the most cloud cover is October (Cloud cover 62).
The month with the least cloud cover is February (Cloud cover 23).

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Average visibility in September
Alajuela, Costa Rica

Average visibility in September - Alajuela, Costa Rica
  • Average visibility in September: 6km

The months with the highest visibility are January, February, March and April (9km).
The months with the lowest visibility are September and October (6km).

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Alajuela, Costa Rica

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