September weather forecast and climate
San Quentin, CA

Weather in September

The first month of the autumn, September, is still a pleasant month in San Quentin, California, with average temperature ranging between min 56.1°F (13.4°C) and max 72.3°F (22.4°C).

Temperature

September is the warmest month, with an average high-temperature of 72.3°F (22.4°C) and an average low-temperature of 56.1°F (13.4°C).

Humidity

In San Quentin, California, the average relative humidity is 71%.

Rainfall

June through September are months with the least rain in San Quentin, California, when the rain falls for 1.7 days and typically aggregates up to 0.04" (1mm) of rain.

Daylight

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

Sunshine

The average sunshine in San Quentin is 10.4h.

UV index

Months with the highest UV index are April, June through September, with an average maximum UV index of 5. A UV Index estimate of 3 to 5 represents a moderate threat to health from unsafe exposure to the UV radiation for average individuals.
Note: The average daily UV index of 5 in September transform into the following instructions:
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. A wide-brim hat offers excellent sun protection for eyes, ears, face, and neck. Sunglasses with UVA and UVB protection significantly reduce eye damage from sun exposure. Tightly woven, loose-fitting clothes provide additional protection from the Sun.
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FAQ

What is the warmest month in San Quentin?

With an average high-temperature of 72.3°F (22.4°C) and an average low-temperature of 56.1°F (13.4°C), September is the warmest month.

What is the temperature in September in San Quentin?

In September, in San Quentin, California, the average high-temperature is 72.3°F (22.4°C), and the average low-temperature is 56.1°F (13.4°C).

What is the average humidity in September in San Quentin?

The average relative humidity in September is 71%.

How much does it rain in San Quentin in September?

In San Quentin, during September, the rain falls for 1.7 days and regularly aggregates up to 0.04" (1mm) of precipitation.

What is the driest month in San Quentin?

June through September are months with the least rain in San Quentin when the rain falls for 1.7 days and typically aggregates up to 0.04" (1mm) of rain.

What is the average length of the day in September in San Quentin?

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

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

In September, the average sunshine in San Quentin is 10.4h.

What is the month with the highest UV index in San Quentin?

April, June through September, with an average maximum UV index of 5, are months with the highest UV index in San Quentin, California.

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

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

Average temperature in September
San Quentin, CA

Average temperature in September - San Quentin, CA
  • Average high temperature in September: 72.3°F

The warmest month (with the highest average high temperature) is September (72.3°F).
The month with the lowest average high temperature is December (55.4°F).

  • Average low temperature in September: 56.1°F

The month with the highest average low temperature is September (56.1°F).
The coldest month (with the lowest average low temperature) is December (45.3°F).

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Average pressure in September
San Quentin, CA

Average pressure in September - San Quentin, 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
San Quentin, CA

Average wind speed in September - San Quentin, CA
  • Average wind speed in September: 5.9mph

The windiest month (with the highest average wind speed) is May (7.8mph).
The calmest months (with the lowest average wind speed) are October and November (5.5mph).

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Average humidity in September
San Quentin, CA

Average humidity in September - San Quentin, CA
  • Average humidity in September: 71%

The month with the highest relative humidity is March (77%).
The month with the lowest relative humidity is October (68%).

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Average rainfall in September
San Quentin, CA

Average rainfall in September - San Quentin, CA
  • Average rainfall in September: 0.04"

The wettest month (with the highest rainfall) is February (0.87").
The driest months (with the least rainfall) are June, July, August and September (0.04").

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Average rainfall days in September
San Quentin, CA

Average rainfall days in September - San Quentin, CA
  • Average rainfall days in September: 1.7 days

The month with the highest number of rainy days is March (8.8 days).
Months with the least rainy days are June and August (1.2 days).

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Average daylight in September /
Average sunshine in September
San Quentin, CA

Average daylight in September / Average sunshine in September - San Quentin, 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: 9.6h).

  • Average sunshine in September: 10.4h

The month with the most sunshine is July (Average sunshine: 11.2h).
The month with the least sunshine is December (Average sunshine: 5.5h).

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Average sunshine days in September
San Quentin, CA

Average sunshine days in September - San Quentin, CA
  • Average sunshine days in September: 26 days

The month with the most sunshine days is June (26.4 days).
The month with the least sunshine days is March (20.7 days).

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Average UV index in September
San Quentin, CA

Average UV index in September - San Quentin, CA
  • Average UV index in September: 5

Months with the highest UV index are April, June, July, August and September (UV index 5).
Months with the lowest UV index are January, February, November and December (UV index 3).

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Average cloud cover in September
San Quentin, CA

Average cloud cover in September - San Quentin, CA
  • Average cloud cover in September: 19

The month with the most cloud cover is March (Cloud cover 39).
The month with the least cloud cover is September (Cloud cover 19).

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Average visibility in September
San Quentin, CA

Average visibility in September - San Quentin, 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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