September weather forecast
San José, Costa Rica

Skyscape of San José, Costa Rica in the evening sun
Skyscape of San José, Costa Rica in the evening sun

Weather in September

September, the first month of the autumn in San José, is also a moderately hot month, with an average temperature ranging between max 23°C (73.4°F) and min 16.4°C (61.5°F).

Temperature

In San José, the average high-temperature in September is practically the same as in August - a still moderately hot 23°C (73.4°F). The average low-temperature, in San José, is 16.4°C (61.5°F).

Humidity

September and October, with an average relative humidity of 91%, are the most humid months.

Rainfall

In San José, Costa Rica, in September, during 29.5 rainfall days, 344mm (13.54") of precipitation is typically accumulated. In San José, during the entire year, the rain falls for 287.8 days and collects up to 2585mm (101.77") of precipitation.

Daylight

In September, the average length of the day in San José is 12h and 11min.
On the first day of September in San José, sunrise is at 05:27 and sunset at 17:45. On the last day of the month, sunrise is at 05:24 and sunset at 17:27 CST.

Sunshine

In San José, the average sunshine in September is 6.5h.

UV index

The months with the highest UV index in San José, Costa Rica, are January through December, with an average maximum UV index of 5. The months with the lowest UV index are January through December, with an average maximum UV index of 5. A UV Index of 3 to 5 symbolizes a medium vulnerability from unsafe exposure to UV radiation for ordinary individuals.
Note: The average daily UV index of 5 in September transform into the following instructions:
Take precautions - Protection against skin and eye damage is obliged. The Sun's most intense and consequently most harmful UV radiation during midday hours should be decreased by minimizing exposure and seeking shade. Sun-protective clothing, a long-sleeved shirt and pants, a wide-brimmed hat, and UVA and UVB-blocking sunglasses are particularly helpful in blocking UV radiation's harmful effects.
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FAQ

What is the temperature in September in San José?

In San José, in September, the average high-temperature is 23°C (73.4°F), and the average low-temperature is 16.4°C (61.5°F).

What are the most humid months in San José?

The months with the highest humidity in San José are September and October, with an average relative humidity of 91%.

What is the average humidity in September in San José?

The average relative humidity in September in San José is 91%.

How much does it rain in San José in September?

In September, the rain falls for 29.5 days. Throughout September, 344mm (13.54") of precipitation is accumulated.

How many hours of daylight does San José have in September?

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

When are sunrise and sunset in September in San José?

On the first day of September, sunrise is at 05:27 and sunset at 17:45. On the last day of the month, sunrise is at 05:24 and sunset at 17:27 CST.

How many hours of sunshine does San José have in September?

In San José, Costa Rica, the average sunshine duration in September is 6.5h.

What are the months with the highest UV index in San José?

The months with the highest UV index in San José are January through December, with an average maximum UV index of 5.

What is the month with the lowest UV index in San José?

January through December, with an average maximum UV index of 5, are months with the lowest UV index in San José.

How high is the UV index in September in San José?

The average daily maximum UV index in September in San José is 5. A UV Index value of 3 to 5 symbolizes a moderate vulnerability from unsafe exposure to Sun's UV rays.

Average temperature in September
San José, Costa Rica

Average temperature in September - San José, Costa Rica
  • Average high temperature in September: 23°C

The warmest month (with the highest average high temperature) is April (26°C).
The month with the lowest average high temperature is October (22.4°C).

  • Average low temperature in September: 16.4°C

The month with the highest average low temperature is June (17°C).
The coldest month (with the lowest average low temperature) is January (13.8°C).

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Average pressure in September
San José, Costa Rica

Average pressure in September - San José, Costa Rica
  • Average pressure in September: 1011.1mbar

The month with the highest atmospheric pressure is January (1012.3mbar).
The month with the lowest atmospheric pressure is October (1010.8mbar).

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Average wind speed in September
San José, Costa Rica

Average wind speed in September - San José, Costa Rica
  • Average wind speed in September: 4.3km/h

The windiest month (with the highest average wind speed) is February (10.7km/h).
The calmest month (with the lowest average wind speed) is September (4.3km/h).

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Average humidity in September
San José, Costa Rica

Average humidity in September - San José, Costa Rica
  • Average humidity in September: 91%

The months with the highest relative humidity are September and October (91%).
The months with the lowest relative humidity are February and March (75%).

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Average rainfall in September
San José, Costa Rica

Average rainfall in September - San José, Costa Rica
  • Average rainfall in September: 344mm

The wettest month (with the highest rainfall) is October (438mm).
The driest month (with the least rainfall) is February (26mm).

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Average rainfall days in September
San José, Costa Rica

Average rainfall days in September - San José, Costa Rica
  • Average rainfall days in September: 29.5 days

The month with the highest number of rainy days is October (30.5 days).
The month with the least rainy days is February (12.2 days).

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Average daylight in September /
Average sunshine in September
San José, Costa Rica

Average daylight in September / Average sunshine in September - San José, Costa Rica
  • Average daylight in September: 12h and 11min

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 34min).

  • Average sunshine in September: 6h and 30min

The month with the most sunshine is February (Average sunshine: 9h and 12min).
The month with the least sunshine is October (Average sunshine: 5h and 48min).

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Average sunshine days in September
San José, Costa Rica

Average sunshine days in September - San José, Costa Rica
  • Average sunshine days in September: 0.1 days

The month with the most sunshine days is March (13.5 days).
The month with the least sunshine days is September (0.1 days).

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Average UV index in September
San José, Costa Rica

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

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

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Average cloud cover in September
San José, Costa Rica

Average cloud cover in September - San José, Costa Rica
  • Average cloud cover in September: 65

The month with the most cloud cover is October (Cloud cover 68).
The month with the least cloud cover is February (Cloud cover 30).

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Average visibility in September
San José, Costa Rica

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

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

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