September weather forecast and climate
Forestville, CA

Weather in September

The first month of the autumn, September, is also a moderately hot month in Forestville, California, with average temperature fluctuating between 53.6°F (12°C) and 82.2°F (27.9°C).

Temperature

In September, the average high-temperature is practically the same as in August - a still warm 82.2°F (27.9°C). In September, the average low-temperature is 53.6°F (12°C).

Heat index

In September, the average heat index is estimated at 84.4°F (29.1°C). Exhaustion is likely with prolonged exposure and activity. Sustaining activity may result in heat cramps.
Note that heat index values are valued for light wind and location in the shade. With the 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', 'feels like', 'real feel', or 'felt air temperature', is an index that combines air temperature and relative humidity to determine the human-perceived temperature equivalent. Additional factors like pregnancy, wind, metabolic differences, and activity influence one's weather impression. Be aware that direct exposure to sunlight increases heat impact, and may raise the heat index additionally, 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.

Humidity

The least humid month is September, with an average relative humidity of 58%.

Rainfall

In Forestville, it is raining for 2.5 days, with typically 0.12" (3mm) of accumulated precipitation. Throughout the year, in Forestville, there are 80.5 rainfall days, and 17.6" (447mm) of precipitation is accumulated.

Daylight

In Forestville, the average length of the day in September is 12.4h.

Sunshine

In September, the average sunshine in Forestville is 11h.

UV index

In September, the average daily maximum UV index in Forestville, California, is 5. A UV Index of 3 to 5 symbolizes a moderate health risk from the exposure to the Sun's UV radiation for average individuals.
Note: In September, the average maximum UV index of 5 translate into the following recommendations:
Take precautions - Protection against sun damage is advised. The Sun's most intense and consequently most harmful UV radiation during midday hours should be decreased by minimizing exposure and seeking shade. 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.
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FAQ

What is the temperature in September in Forestville?

In Forestville, California, in September, the average high-temperature is 82.2°F (27.9°C), and the average low-temperature is 53.6°F (12°C). In September, the average heat index (a.k.a. 'felt air temperature', 'real feel'), that combines both air temperature and relative humidity, is evaluated at 84.4°F (29.1°C).

What is the least humid month in Forestville?

With an average relative humidity of 58%, September is the least humid month.

What is the average humidity in September in Forestville?

The average relative humidity in September in Forestville is 58%.

How much does it rain in Forestville in September?

In Forestville, California, during September, the rain falls for 2.5 days and regularly aggregates up to 0.12" (3mm) of precipitation.

How many hours of daylight does Forestville have in September?

The average length of the day in September is 12.4h.

How long on average sun shines in September in Forestville?

The average sunshine in September in Forestville is 11h.

What is the UV index reading in September in Forestville?

In September, the average daily maximum UV index in Forestville is 5. A UV Index value of 3 to 5 symbolizes a moderate vulnerability from unprotected exposure to the UV radiation.

Average temperature in September
Forestville, CA

Average temperature in September - Forestville, CA
  • Average high temperature in September: 82.2°F

The warmest month (with the highest average high temperature) is August (83.5°F).
The month with the lowest average high temperature is December (55.8°F).

  • Average low temperature in September: 53.6°F

The month with the highest average low temperature is August (54.3°F).
The coldest month (with the lowest average low temperature) is December (40.5°F).

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Average pressure in September
Forestville, CA

Average pressure in September - Forestville, CA
  • Average pressure in September: 29.92"

The month with the highest atmospheric pressure is January (30.13").
Months with the lowest atmospheric pressure are June, August and September (29.92").

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Average wind speed in September
Forestville, CA

Average wind speed in September - Forestville, CA
  • Average wind speed in September: 4.7mph

The windiest month (with the highest average wind speed) is May (6.4mph).
The calmest month (with the lowest average wind speed) is November (4.5mph).

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Average humidity in September
Forestville, CA

Average humidity in September - Forestville, CA
  • Average humidity in September: 58%

The month with the highest relative humidity is March (76%).
The month with the lowest relative humidity is September (58%).

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Average rainfall in September
Forestville, CA

Average rainfall in September - Forestville, CA
  • Average rainfall in September: 0.12"

The wettest month (with the highest rainfall) is February (3.78").
The driest months (with the least rainfall) are July and August (0.04").

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Average rainfall days in September
Forestville, CA

Average rainfall days in September - Forestville, CA
  • Average rainfall days in September: 2.5 days

The month with the highest number of rainy days is March (14.3 days).
The month with the least rainy days is July (1 days).

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Average daylight in September /
Average sunshine in September
Forestville, CA

Average daylight in September / Average sunshine in September - Forestville, CA
  • Average daylight in September: 12.4h

The month with the longest days is June (Average daylight: 14.8h).
The month with the shortest days is December (Average daylight: 9.5h).

  • Average sunshine in September: 11h

The month with the most sunshine is July (Average sunshine: 12h).
The month with the least sunshine is December (Average sunshine: 5.6h).

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Average sunshine days in September
Forestville, CA

Average sunshine days in September - Forestville, CA
  • Average sunshine days in September: 27 days

The month with the most sunshine days is July (29.1 days).
The month with the least sunshine days is March (15.3 days).

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Average UV index in September
Forestville, CA

Average UV index in September - Forestville, CA
  • Average UV index in September: 5

Months with the highest UV index are June, July and August (UV index 6).
Months with the lowest UV index are January, February, November and December (UV index 3).

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Average cloud cover in September
Forestville, CA

Average cloud cover in September - Forestville, CA
  • Average cloud cover in September: 10

The month with the most cloud cover is March (Cloud cover 41).
The month with the least cloud cover is July (Cloud cover 8).

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Average visibility in September
Forestville, CA

Average visibility in September - Forestville, CA
  • Average visibility in September: 6mi

Months with the highest visibility are January, February, March, April, May, June, July, August, September, October, November and December (6mi).
Months with the lowest visibility are January, February, March, April, May, June, July, August, September, October, November and December (6mi).

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