September weather forecast
San Quentin, CA

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Weather in September

The first month of the autumn, September, is still a pleasant month in San Quentin, California, with temperature in the range of an average low of 56.1°F (13.4°C) and an average high of 72.3°F (22.4°C).

Temperature

September registers as the month with the highest average temperatures, reaching 72.3°F (22.4°C) at its peak and 56.1°F (13.4°C) at the lowest.

Humidity

In September, the average relative humidity is 71%.

Rainfall

The months with the least rainfall are June through September Rain falls for 1.7 days and accumulates 0.04" (1mm) of rain.

Daylight

In September, the average length of the day in San Quentin is 12h and 25min.
On the first day of September, sunrise is at 6:40 am and sunset at 7:38 pm. On the last day of the month, sunrise is at 7:05 am and sunset at 6:53 pm PDT.

Sunshine

In September, the average sunshine is 10.4h.

UV index

The months with the highest UV index in San Quentin are April, June through September, with an average maximum UV index of 5. A UV Index reading of 3 to 5 represents a moderate threat to health from unsafe exposure to UV radiation for the average person.
Note: In September, the UV index of 5 transforms into the following advice:
Be vigilant - Preventing sunburn is recommended. Avoid the Sun's strongest UV rays by seeking shade and limiting exposure during midday. During bright days, sunglasses that offer UVA and UVB defense are recommended.
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Frequently asked questions

What is the warmest month in San Quentin?

In San Quentin, September is the warmest month, with temperatures averaging a high of 72.3°F (22.4°C) and a low of 56.1°F (13.4°C).

What are the temperatures in San Quentin in September?

San Quentin in September has an average high-temperature of 72.3°F (22.4°C) and an average low-temperature of 56.1°F (13.4°C).

What is the average humidity in September in San Quentin?

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

What is the driest month in San Quentin?

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.

How much does it rain in San Quentin in September?

In San Quentin, California, in September, it is raining for 1.7 days, with typically 0.04" (1mm) of accumulated precipitation.

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

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

What time are sunrise and sunset in September in San Quentin?

In September, on the first day of the month, sunrise is at 6:40 am and sunset at 7:38 pm. On the last day of the month, sunrise is at 7:05 am and sunset at 6:53 pm PDT.

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

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

When is 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.

What is the UV index reading in September in San Quentin?

In September, the average daily maximum UV index in San Quentin, California, is 5. A UV Index reading of 3 to 5 represents a medium health risk from unsafe exposure to Sun's UV rays.
Average humidity
Average rainfall days
Average daylight
Average sunshine
Average sunshine days
Average UV index
Average cloud cover
Average visibility

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"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
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).
The 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: 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 36min).

  • Average sunshine in September: 10h and 2min

The month with the most sunshine is July (Average sunshine: 11h and 12min).
The month with the least sunshine is December (Average sunshine: 5h and 30min).

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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

The months with the highest UV index are April, June, July, August and September (UV index 5).
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
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

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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San Quentin, California, USA

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