September weather forecast
Richmond, CA

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Richmond and Golden Gate residential districts as split by the scenic natural park
Richmond and Golden Gate residential districts as split by the scenic natural park

Weather in September

The first month of the autumn, September, is also a moderately hot month in Richmond, California, with an average temperature fluctuating between 75.7°F (24.3°C) and 56.5°F (13.6°C).

Temperature

In Richmond, September is the month with the highest recorded average temperatures, measuring a high of 75.7°F (24.3°C) and a low of 56.5°F (13.6°C).

Humidity

In Richmond, the average relative humidity in September is 66%.

Rainfall

The months with the least rainfall in Richmond are June through September Rain falls for 2.5 days and accumulates 0.08" (2mm) of rain.

Ocean temperature

September is the month with the warmest seawater in Richmond, with an average ocean temperature of 57.4°F (14.1°C).
Note: Entering waters of 57.4°F (14.1°C) is life-endangering. A mere moment in 55.4°F (13°C) waters feels piercing cold, and below 50°F (10°C) it can lead to immediate cold shock and cessation of breathing control, depending on body resilience.

Daylight

In September, the average length of the day in Richmond, California, is 12h and 25min.
On the first day of the month, sunrise is at 6:40 am and sunset at 7:38 pm. On the last day of September, sunrise is at 7:04 am and sunset at 6:53 pm PDT.

Sunshine

In Richmond, California, the average sunshine in September is 10.8h.

UV index

The months with the highest UV index in Richmond, California, are April 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 rays for the ordinary person.
Note: The daily high UV index of 5 during September translates into the following recommendations:
Take precautions - Protection against sun damage is advised. To guard against the harmful effects of the Sun, minimize exposure during midday. In bright sunlight, prioritize sunglasses that grant protection from UVA and UVB radiation.
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Frequently asked questions

What is the warmest month in Richmond?

September, recognised by an average high temperature of 75.7°F (24.3°C) and a low of 56.5°F (13.6°C), is Richmond's warmest month.

What is the temperature in September in Richmond?

The average high-temperature, in September, in Richmond, is 75.7°F (24.3°C), while the average low-temperature is 56.5°F (13.6°C).

What is the average humidity in September in Richmond?

In Richmond, California, the average relative humidity in September is 66%.

What is the driest month in Richmond?

June through September are months with the least rain in Richmond, California, when the rain falls for 2.5 days and typically aggregates up to 0.08" (2mm) of rain.

How much does it rain in Richmond in September?

In Richmond, in September, during 2.5 rainfall days, 0.08" (2mm) of precipitation is typically accumulated.

What is the month with the warmest ocean in Richmond?

September is the month with the warmest seawater, with an average ocean temperature of 57.4°F (14.1°C).

What is the water temperature in September in Richmond?

In Richmond, California, the average seawater temperature in September is 57.4°F (14.1°C). Swimming in 57.4°F (14.1°C) is considered dangerous. Unprotected immersion in temperatures below 50°F (10°C) causes quickly maximum intensity cold shock with hyperventilation.

How many hours of daylight does Richmond have in September?

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

When is the sunrise / sunset in September in Richmond?

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, in Richmond, California, sunrise is at 7:04 am and sunset at 6:53 pm PDT.

How many hours of sunshine does Richmond have in September?

In September, the average sunshine duration in Richmond, California, is 10.8h.

What is the month with the highest UV index in Richmond?

The months with the highest UV index are April through September, with an average maximum UV index of 5.

How high is the UV index in September in Richmond?

In Richmond, the average daily maximum UV index in September is 5. A UV Index of 3 to 5 symbolizes a moderate vulnerability from exposure to the Sun's 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
Richmond, CA

Average temperature in September - Richmond, CA
  • Average high temperature in September: 75.7°F

The warmest month (with the highest average high temperature) is September (75.7°F).
The month with the lowest average high temperature is December (55.6°F).

  • Average low temperature in September: 56.5°F

The month with the highest average low temperature is September (56.5°F).
The coldest month (with the lowest average low temperature) is January (44.8°F).

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Average pressure in September
Richmond, CA

Average pressure in September - Richmond, 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
Richmond, CA

Average wind speed in September - Richmond, CA
  • Average wind speed in September: 5.7mph

The windiest month (with the highest average wind speed) is May (7.5mph).
The calmest month (with the lowest average wind speed) is November (5.1mph).

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Average humidity in September
Richmond, CA

Average humidity in September - Richmond, CA
  • Average humidity in September: 66%

The month with the highest relative humidity is March (75%).
The month with the lowest relative humidity is October (65%).

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Average rainfall in September
Richmond, CA

Average rainfall in September - Richmond, CA
  • Average rainfall in September: 0.08"

The wettest month (with the highest rainfall) is February (1.38").
The driest months (with the least rainfall) are June, July, August and September (0.08").

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Average rainfall days in September
Richmond, CA

Average rainfall days in September - Richmond, CA
  • Average rainfall days in September: 2.5 days

The month with the highest number of rainy days is March (10.8 days).
The month with the least rainy days is June (2 days).

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Average sea temperature in September
Richmond, CA

Average sea temperature in September - Richmond, CA
  • Average sea temperature in September: 57.3°F

The best month for swimming (with the highest average sea temperature) is September (57.3°F).
The coldest months (with the lowest average sea temperature) are April and June (53°F).

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

Average daylight in September / Average sunshine in September - Richmond, 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 5min

The month with the most sunshine is July (Average sunshine: 11h and 48min).
The month with the least sunshine is December (Average sunshine: 5h and 42min).

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Average sunshine days in September
Richmond, CA

Average sunshine days in September - Richmond, CA
  • Average sunshine days in September: 24.5 days

The month with the most sunshine days is July (24.9 days).
The month with the least sunshine days is March (18.4 days).

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Average UV index in September
Richmond, CA

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

The months with the highest UV index are April, May, 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
Richmond, CA

Average cloud cover in September - Richmond, CA
  • Average cloud cover in September: 15

The month with the most cloud cover is March (Cloud cover 37).
The month with the least cloud cover is July (Cloud cover 14).

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Average visibility in September
Richmond, CA

Average visibility in September - Richmond, 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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Richmond, California, USA

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