September weather forecast
Graton, CA

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Weather in September

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

Temperature

With September's arrival, Graton's weather records an average high-temperature of a still warm 79°F (26.1°C), marking little difference from August's 79.7°F (26.5°C). A dramatic downturn marks the September nights, with lows averaging at a cool 54.7°F (12.6°C).

Humidity

With an average relative humidity of 63%, September is the least humid month.

Rainfall

In September, the rain falls for 2.8 days. Throughout September, 0.12" (3mm) of precipitation is accumulated. Throughout the year, in Graton, there are 72.8 rainfall days, and 12.01" (305mm) of precipitation is accumulated.

Daylight

In Graton, California, the average length of the day in September is 12h and 25min.
On the first day of September in Graton, California, sunrise is at 6:41 am and sunset at 7:40 pm. On the last day of the month, sunrise is at 7:07 am and sunset at 6:55 pm PDT.

Sunshine

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

UV index

In September, the average daily maximum UV index is 5. A UV Index reading of 3 to 5 represents a moderate health risk from unprotected exposure to Sun's UV rays for ordinary individuals.
Note: The maximum daily UV index of 5 during September translates into the following directions:
Guard yourself - An obligation to protect skin and eyes from harm exists. Stay safe from the Sun's strongest UV rays by limiting exposure during midday. Employ a hat with a wide brim for robust protection, cutting UV exposure by half.
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Frequently asked questions

What are the temperatures in Graton in September?

In September, in Graton, the average high-temperature is 79°F (26.1°C), and 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, with an average relative humidity of 63%.

What is the average humidity in September in Graton?

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

How much does it rain in Graton in September?

In Graton, in September, it is raining for 2.8 days, with typically 0.12" (3mm) of accumulated precipitation.

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

The average day length in September in Graton, California, is 12h and 25min.

What time are sunrise and sunset in September in Graton?

In September, on the first day of the month, sunrise is at 6:41 am and sunset at 7:40 pm. On the last day of the month, sunrise is at 7:07 am and sunset at 6:55 pm PDT.

How many hours of sunshine does Graton have in September?

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

What is the UV index intensity in September in Graton?

In Graton, the average daily maximum UV index in September is 5. A UV Index of 3 to 5 symbolizes a moderate vulnerability from unprotected exposure to UV radiation.
Average humidity
Average rainfall days
Average daylight
Average sunshine
Average sunshine days
Average UV index
Average cloud cover
Average visibility

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

The 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"Hg

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

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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: 12h and 2min

The month with the longest days is June (Average daylight: 14h and 48min).
The month with the shortest days is December (Average daylight: 9h and 30min).

  • Average sunshine in September: 11h and 0min

The month with the most sunshine is July (Average sunshine: 11h and 54min).
The month with the least sunshine is December (Average sunshine: 5h and 42min).

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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).
The 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

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

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Graton, California, USA

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