September weather forecast and climate
San Ramon, CA

A street in San Ramon, California, featuring a stunning beauty of golden and brown trees on both sides of the road, during autumn
A street in San Ramon, California, featuring a stunning beauty of golden and brown trees on both sides of the road, during autumn

Weather in September

The first month of the autumn, September, is still a warm month in San Ramon, California, with average temperature varying between 56.5°F (13.6°C) and 82°F (27.8°C).

Temperature

In September, the average high-temperature is practically the same as in August - a still moderately hot 82°F (27.8°C). In September, in San Ramon, the average low-temperature is 56.5°F (13.6°C).

Heat index

In September, the average heat index is calculated to 84°F (28.9°C). Constant exposure and activity lead to possible fatigue. Prolonged exercise may result in heat cramps.
Take into consideration that the heat index values are calculated for shade and light wind conditions. Exposure to direct sunshine can increase heat index values by up to 15 Fahrenheit (8 Celsius) degrees.
Note: The heat index, also known as 'apparent temperature', 'real feel', 'feels like', or 'felt air temperature', is an index that combines air temperature and relative humidity to determine the human-perceived temperature equivalent. Additional factors like activity, clothing, pregnancy, and wind affect individual temperature impact. Be aware that direct exposure to sunlight increases heat impact, and may raise the heat index additionally, by up to 15 Fahrenheit (8 Celsius) degrees. Heat index values are especially crucial for babies and toddlers. Young children are generally more endangered than adults, as they usually less sweat. And also, due to larger skin surface relative to their small bodies and higher heat production as a result of their activity.

Humidity

With an average relative humidity of 57%, September is the least humid month.

Rainfall

In San Ramon, during September, the rain falls for 1.8 days and regularly aggregates up to 0.08" (2mm) of precipitation. In San Ramon, during the entire year, the rain falls for 67.2 days and collects up to 10.98" (279mm) of precipitation.

Daylight

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

Sunshine

In September, the average sunshine is 11.2h.

UV index

In San Ramon, the average daily maximum UV index in September is 5. A UV Index of 3 to 5 symbolizes a moderate threat to health from unprotected exposure to the Sun's UV rays for average individuals.
Note: The daily maximum UV index of 5 interpret into the following advice:
Take precautions - Protection against sunburn is recommended. The Sun's most intense and consequently most harmful UV radiation during midday hours should be decreased by minimizing exposure and seeking shade. Sun-protective clothing, a long-sleeved shirt and pants, a wide-brimmed hat, and UVA and UVB-blocking sunglasses are particularly helpful in blocking UV radiation's harmful effects.
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FAQ

What is the temperature in September in San Ramon?

In September, the average high-temperature is 82°F (27.8°C), and the average low-temperature is 56.5°F (13.6°C). The average heat index (a.k.a. 'real feel', 'apparent temperature'), that calculates temperature value influenced by the moisture in the air, in September is calculated to 84°F (28.9°C).

What is the least humid month in San Ramon?

September is the least humid month in San Ramon, with an average relative humidity of 57%.

What is the average humidity in September in San Ramon?

In September, the average relative humidity in San Ramon, California, is 57%.

How much does it rain in San Ramon in September?

In San Ramon, during September, the rain falls for 1.8 days and regularly aggregates up to 0.08" (2mm) of precipitation.

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

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

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

In September, the average sunshine in San Ramon, California, is 11.2h.

What is the UV index intensity in September in San Ramon?

In September, the average daily maximum UV index in San Ramon is 5. A UV Index value of 3 to 5 symbolizes a medium hazard to health from unprotected exposure to the UV radiation.

Average temperature in September
San Ramon, CA

Average temperature in September - San Ramon, CA
  • Average high temperature in September: 82°F

The warmest month (with the highest average high temperature) is July (83.7°F).
The month with the lowest average high temperature is December (55.9°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 December (42.1°F).

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Average pressure in September
San Ramon, CA

Average pressure in September - San Ramon, CA
  • Average pressure in September: 29.92"

The month with the highest atmospheric pressure is January (30.14").
Months with the lowest atmospheric pressure are June, August and September (29.92").

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Average wind speed in September
San Ramon, CA

Average wind speed in September - San Ramon, CA
  • Average wind speed in September: 5.2mph

The windiest month (with the highest average wind speed) is May (6.7mph).
The calmest month (with the lowest average wind speed) is November (4.2mph).

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Average humidity in September
San Ramon, CA

Average humidity in September - San Ramon, CA
  • Average humidity in September: 57%

The month with the highest relative humidity is March (74%).
The month with the lowest relative humidity is September (57%).

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Average rainfall in September
San Ramon, CA

Average rainfall in September - San Ramon, CA
  • Average rainfall in September: 0.08"

The wettest month (with the highest rainfall) is February (2.28").
The driest month (with the least rainfall) is July (0").

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Average rainfall days in September
San Ramon, CA

Average rainfall days in September - San Ramon, CA
  • Average rainfall days in September: 1.8 days

The month with the highest number of rainy days is March (12.6 days).
The month with the least rainy days is August (0.6 days).

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

Average daylight in September / Average sunshine in September - San Ramon, CA
  • Average daylight in September: 12.4h

The month with the longest days is June (Average daylight: 14.7h).
The month with the shortest days is December (Average daylight: 9.6h).

  • Average sunshine in September: 11.2h

The month with the most sunshine is July (Average sunshine: 12.1h).
The month with the least sunshine is December (Average sunshine: 5.8h).

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Average sunshine days in September
San Ramon, CA

Average sunshine days in September - San Ramon, CA
  • Average sunshine days in September: 27.5 days

The month with the most sunshine days is July (29.9 days).
The month with the least sunshine days is March (17.5 days).

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Average UV index in September
San Ramon, CA

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

Months with the highest UV index are June, July and August (UV index 6).
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 Ramon, CA

Average cloud cover in September - San Ramon, CA
  • Average cloud cover in September: 10

The month with the most cloud cover is March (Cloud cover 36).
The month with the least cloud cover is July (Cloud cover 6).

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Average visibility in September
San Ramon, CA

Average visibility in September - San Ramon, 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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