September weather forecast and climate
Graton, CA

Weather in September

September, the first month of the autumn, in Graton, is still a warm month, with average temperature varying between 54.7°F (12.6°C) and 79°F (26.1°C).

Temperature

In September, the average high-temperature is relatively the same as in August - a still moderately hot 79°F (26.1°C). In Graton, in September, the average low-temperature is 54.7°F (12.6°C).

Humidity

September is the least humid month in Graton, with an average relative humidity of 63%.

Rainfall

In Graton, California, it is raining for 2.8 days, with typically 0.12" (3mm) of accumulated precipitation. Throughout the year, there are 72.8 rainfall days, and 12.01" (305mm) of precipitation is accumulated.

Daylight

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

Sunshine

The average sunshine in Graton, California, is 11h.

UV index

In Graton, the average daily maximum UV index in September is 5. A UV Index value of 3 to 5 symbolizes a moderate health risk from the exposure to the Sun's UV rays for the ordinary person.
Note: The daily maximum UV index of 5 interpret into the following advice:
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. 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 Graton?

The average high-temperature, in September, in Graton, is 79°F (26.1°C), while the average low-temperature is 54.7°F (12.6°C).

What is the least humid month in Graton?

September is the least humid month in Graton, with an average relative humidity of 63%.

What is the average humidity in September in Graton?

In Graton, the average relative humidity in September is 63%.

How many days does it rain in September in Graton?

In Graton, California, in September, during 2.8 rainfall days, 0.12" (3mm) of precipitation is typically accumulated.

How many hours of daylight does Graton have in September?

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

How many hours of sunshine does Graton have in September?

The average sunshine in September in Graton, California, is 11h.

What is the UV index reading in September in Graton?

The average daily maximum UV index in September in Graton is 5. A UV Index reading of 3 to 5 represents a medium health risk from the exposure to the Sun's UV radiation.

Average temperature in September
Graton, CA

Average temperature in September - Graton, CA
  • Average high temperature in September: 79°F

The warmest month (with the highest average high temperature) is August (79.7°F).
The month with the lowest average high temperature is December (55.6°F).

  • Average low temperature in September: 54.7°F

Months with the highest average low temperature are August and September (54.7°F).
The coldest month (with the lowest average low temperature) is December (41.9°F).

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Average pressure in September
Graton, CA

Average pressure in September - Graton, 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
Graton, CA

Average wind speed in September - Graton, CA
  • Average wind speed in September: 5.2mph

The windiest month (with the highest average wind speed) is May (7.1mph).
The calmest month (with the lowest average wind speed) is November (4.9mph).

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Average humidity in September
Graton, CA

Average humidity in September - Graton, CA
  • Average humidity in September: 63%

The month with the highest relative humidity is March (77%).
The month with the lowest relative humidity is September (63%).

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Average rainfall in September
Graton, CA

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

The wettest month (with the highest rainfall) is February (2.64").
The driest months (with the least rainfall) are July and August (0.04").

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Average rainfall days in September
Graton, CA

Average rainfall days in September - Graton, CA
  • Average rainfall days in September: 2.8 days

The month with the highest number of rainy days is March (12.6 days).
The month with the least rainy days is August (0.8 days).

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

Average daylight in September / Average sunshine in September - Graton, 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: 11.9h).
The month with the least sunshine is December (Average sunshine: 5.7h).

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Average sunshine days in September
Graton, CA

Average sunshine days in September - Graton, CA
  • Average sunshine days in September: 26.5 days

The month with the most sunshine days is July (27.2 days).
The month with the least sunshine days is March (17.1 days).

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Average UV index in September
Graton, CA

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

The month with the highest UV index is June (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
Graton, CA

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

The month with the most cloud cover is March (Cloud cover 39).
The month with the least cloud cover is July (Cloud cover 9).

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Average visibility in September
Graton, CA

Average visibility in September - Graton, 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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