September weather forecast
Antioch, CA

A high bridge passing over the famous San Joaquin River Delta in Antioch, California
A high bridge passing over the famous San Joaquin River Delta in Antioch, California

Weather in September

September, the first month of the autumn in Antioch, is still a warm month, with an average temperature varying between 57.7°F (14.3°C) and 85.3°F (29.6°C).

Temperature

In September, the average high-temperature is essentially the same as in August - a warm 85.3°F (29.6°C). The average low-temperature, in Antioch, is 57.7°F (14.3°C).

Heat index

The average heat index in September is calculated to be a tropical 87.4°F (30.8°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. With exposure to direct sunlight, the heat index may be increased by up to 15 Fahrenheit (8 Celsius) degrees.
Note: The heat index, also known as 'feels like', 'apparent temperature', 'felt air temperature', or 'real feel', is a measure that combines air temperature and relative humidity into a single value that indicates how hot the weather feels. Additional factors like activity, differences in body mass, height, and shape, pregnancy, and clothing affect individual temperature impact. Be aware that direct exposure to sunlight increases heat impact and may raise the heat index by up to 15 Fahrenheit (8 Celsius) degrees. Heat index values are particularly important for children. 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

The least humid month is September, with an average relative humidity of 52%.

Rainfall

In Antioch, California, during September, the rain falls for 1.3 days and regularly aggregates up to 0.08" (2mm) of precipitation. In Antioch, California, during the entire year, the rain falls for 62 days and collects up to 10.16" (258mm) of precipitation.

Snowfall

In Antioch, snow does not fall in January through November.

Daylight

In September, the average length of the day is 12h and 25min.
On the first day of September in Antioch, sunrise is at 6:37 am and sunset at 7:36 pm. On the last day of the month, sunrise is at 7:02 am and sunset at 6:51 pm PDT.

Sunshine

In September, the average sunshine is 11.2h.

UV index

In Antioch, the average daily maximum UV index in September is 5. A UV Index reading of 3 to 5 represents a medium vulnerability from unprotected exposure to Sun's UV rays for the average person.
Note: The average daily UV index of 5 in September transform into the following instructions:
Take precautions - Protection against skin and eye damage is obliged. The solar radiation is most powerful near the mid-day, so the exposure to the direct Sun should be reduced accordingly. A wide-brim hat offers excellent sun protection for the 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 temperature in September in Antioch?

The average high-temperature, in September, in Antioch, California, is 85.3°F (29.6°C), while the average low-temperature is 57.7°F (14.3°C). The average heat index (a.k.a. 'felt air temperature', 'apparent temperature'), which factors the actual air temperature with the relative humidity, in September is calculated to be 87.4°F (30.8°C).

What is the least humid month in Antioch?

September is the least humid month in Antioch, California, with an average relative humidity of 52%.

What is the average humidity in September in Antioch?

In September, the average relative humidity in Antioch, California, is 52%.

How many days does it rain in September in Antioch?

In Antioch, California, in September, during 1.3 rainfall days, 0.08" (2mm) of precipitation is typically accumulated.

When it does not snow in Antioch?

January through November are months without snowfall in Antioch.

What is the average length of the day in September in Antioch?

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

When is the sunrise / sunset in September in Antioch?

In September, on the first day of the month, sunrise is at 6:37 am and sunset at 7:36 pm. On the last day of the month, sunrise is at 7:02 am and sunset at 6:51 pm PDT.

How many hours of sunshine does Antioch have in September?

The average sunshine duration in September in Antioch, California, is 11.2h.

How high is the UV index in September in Antioch?

In Antioch, California, the average daily maximum UV index in September is 5. A UV Index value of 3 to 5 symbolizes a medium hazard to health from unprotected exposure to UV radiation.
Average humidity
Average rainfall days
Average snowfall days
Average sunshine days
Average UV index
Average cloud cover
Average visibility

Average temperature in September
Antioch, CA

Average temperature in September - Antioch, CA
  • Average high temperature in September: 85.3°F

The warmest month (with the highest average high temperature) is July (88.5°F).
The month with the lowest average high temperature is December (55°F).

  • Average low temperature in September: 57.7°F

The month with the highest average low temperature is September (57.7°F).
The coldest month (with the lowest average low temperature) is January (41.5°F).

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Average pressure in September
Antioch, CA

Average pressure in September - Antioch, CA
  • Average pressure in September: 29.92"Hg

The month with the highest atmospheric pressure is January (30.14"Hg).
The month with the lowest atmospheric pressure is June (29.91"Hg).

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Average wind speed in September
Antioch, CA

Average wind speed in September - Antioch, CA
  • Average wind speed in September: 6.2mph

The windiest month (with the highest average wind speed) is June (7.8mph).
The calmest months (with the lowest average wind speed) are January and November (4.5mph).

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Average humidity in September
Antioch, CA

Average humidity in September - Antioch, CA
  • Average humidity in September: 52%

The month with the highest relative humidity is January (74%).
The month with the lowest relative humidity is September (52%).

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Average rainfall in September
Antioch, CA

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

The wettest month (with the highest rainfall) is February (2.09").
The driest months (with the least rainfall) are July and August (0.04").

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Average rainfall days in September
Antioch, CA

Average rainfall days in September - Antioch, CA
  • Average rainfall days in September: 1.3 days

The month with the highest number of rainy days is March (12.3 days).
The month with the least rainy days is August (0.8 days).

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Average snowfall days in September
Antioch, CA

Average snowfall days in September - Antioch, CA
  • Average snowfall days in September: 0 days

The month with the highest number of snowfall days is December (0.1 days).
The months with the least snowfall days are January, February, March, April, May, June, July, August, September, October and November (0 days).

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

Average daylight in September / Average sunshine in September - Antioch, CA
  • Average daylight in September: 12h and 25min

The month with the longest days is June (Average daylight: 14h and 46min).
The month with the shortest days is December (Average daylight: 9h and 35min).

  • Average sunshine in September: 11h and 12min

The month with the most sunshine is July (Average sunshine: 12h and 6min).
The month with the least sunshine is December (Average sunshine: 5h and 48min).

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Average sunshine days in September
Antioch, CA

Average sunshine days in September - Antioch, CA
  • Average sunshine days in September: 28.5 days

The month with the most sunshine days is August (29.8 days).
The month with the least sunshine days is March (17.7 days).

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Average UV index in September
Antioch, CA

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

The months with the highest UV index are June, July and August (UV index 6).
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
Antioch, CA

Average cloud cover in September - Antioch, CA
  • Average cloud cover in September: 8

The months with the most cloud cover are March and December (Cloud cover 35).
The month with the least cloud cover is July (Cloud cover 5).

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Average visibility in September
Antioch, CA

Average visibility in September - Antioch, 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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