September weather forecast
San Anselmo, CA

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Weather in September

As September arrives, San Anselmo gets a respite from the peak summer heat as temperature highs decline to 72.3°F (22.4°C). It ushers in slightly cooler days and nights, painting a pleasant climate canvas. This is accompanied by the least cloud cover observed in the year at 19%, making for clear sky days. With rain levels consistent at 0.04" (1mm), similar to previous months, it grants continuity to the prolonged dry spell. The wind speed slows further, marking a transition from the summer to fall.

Temperature

September, recognised by an average high temperature of 72.3°F (22.4°C) and a low of 56.1°F (13.4°C), is San Anselmo's warmest month.

Humidity

In September, the average relative humidity is 71%.

Rainfall

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

Daylight

In San Anselmo, the average length of the day in September is 12h and 25min.
On the first day of the month, sunrise is at 6:40 am and sunset at 7:39 pm. On the last day of September, sunrise is at 7:05 am and sunset at 6:54 pm PDT.

Sunshine

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

UV index

The months with the highest UV index in San Anselmo 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 exposure to the Sun's UV radiation for ordinary individuals.
Note: In September, a daily maximum UV index of 5 leads to the following instructions:
Take care. Persons with lighter skin might suffer burns in less than 30 minutes. The best time to avoid the Sun's harmful UV radiation is during midday when it's most potent. For a sun-safe wardrobe, go for clothes that are tightly woven and generously sized.
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Frequently asked questions

What is the warmest month in San Anselmo?

September proves to be the warmest month in San Anselmo, recording an average peak temperature of 72.3°F (22.4°C) and a minimum temperature of 56.1°F (13.4°C).

What is the temperature in September in San Anselmo?

September temperatures in San Anselmo, California, vary between a high-temperature of 72.3°F (22.4°C) and a low-temperature of 56.1°F (13.4°C).

What is the average humidity in September in San Anselmo?

In September, the average relative humidity is 71%.

What is the driest month in San Anselmo?

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

How many days does it rain in September in San Anselmo?

In San Anselmo, 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 Anselmo?

In September, the average day length is 12h and 25min.

When are sunrise and sunset in September in San Anselmo?

On the first day of September in San Anselmo, California, sunrise is at 6:40 am and sunset at 7:39 pm. On the last day of the month, sunrise is at 7:05 am and sunset at 6:54 pm PDT.

How long on average sun shines in September in San Anselmo?

The average sunshine duration in September in San Anselmo is 10.4h.

What are the months with the highest UV index in San Anselmo?

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 Anselmo?

In September, the average daily maximum UV index in San Anselmo is 5. A UV Index estimate of 3 to 5 represents a moderate health threat 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
San Anselmo, CA

Average temperature in September - San Anselmo, 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 Anselmo, CA

Average pressure in September - San Anselmo, 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 Anselmo, CA

Average wind speed in September - San Anselmo, 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 Anselmo, CA

Average humidity in September - San Anselmo, 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 Anselmo, CA

Average rainfall in September - San Anselmo, 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 Anselmo, CA

Average rainfall days in September - San Anselmo, 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 Anselmo, CA

Average daylight in September / Average sunshine in September - San Anselmo, 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 Anselmo, CA

Average sunshine days in September - San Anselmo, 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 Anselmo, CA

Average UV index in September - San Anselmo, 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 Anselmo, CA

Average cloud cover in September - San Anselmo, 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 Anselmo, CA

Average visibility in September - San Anselmo, 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 Anselmo, California, USA

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