September weather forecast
Antioch, CA

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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

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

Temperature

Entering September, Antioch's average high-temperature reads a warm 85.3°F (29.6°C), indicating a close resemblance to the previous month's climate. A striking difference from the daytime highs is registered during September nights in Antioch, with an average temperature of 57.7°F (14.3°C).

Heat index

The heat index in September is calculated to be a tropical 87.8°F (31°C). Prolonged exposure and physical activity might induce exhaustion, potentially causing heat cramps.
Heat index evaluations are typically in the context of light winds and shaded environments. Exposure to direct sunlight may make the heat index values climb by 15 Fahrenheit (8 Celsius) degrees.
Note: The heat index, also known as 'real feel' or 'felt air temperature', offers an insight into how hot it feels when we factor in moisture content. The individual's impression of temperature can be shaped by additional aspects such as metabolic variations, physical activity, and clothing. It is essential to realize that direct sunlight can escalate the perceived temperature, increasing the heat index by 15 Fahrenheit (8 Celsius) degrees. Heat index values remain especially vital for babies and toddlers. Young kids are often more at risk than adults as they tend to perspire less. Besides, their skin surface is larger relative to their small bodies, and their increased heat output from their active lifestyle compounds their risk.

Humidity

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

Rainfall

In Antioch, in September, during 1.3 rainfall days, 0.08" (2mm) of precipitation is typically accumulated. Throughout the year, there are 62 rainfall days, and 10.16" (258mm) of precipitation is accumulated.

Snowfall

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

Daylight

The average length of the day in September is 12h and 25min.
On the first day of the month, sunrise is at 6:37 am and sunset at 7:36 pm. On the last day of September, in Antioch, California, 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 September, the average daily maximum UV index is 5. A UV Index value of 3 to 5 symbolizes a medium vulnerability from exposure to the Sun's UV rays for the average person.
Note: A maximum UV index of 5 in September translates into the following recommendations:
Make use of precautions - Suggestions to resist sunburn are communicated. Considering the Sun's intensity during midday, it's wise to minimize direct exposure. Wearing sunglasses with both UVA and UVB protection effectively reduces sun-induced eye damage.

Frequently asked questions

Is it hot in Antioch during September?

An average high-temperature, in September, in Antioch, is 85.3°F (29.6°C) and the average low-temperature is 57.7°F (14.3°C). The average heat index (a.k.a. 'apparent temperature', 'felt air temperature'), which calculates the temperature value influenced by the moisture in the air, in September is calculated to be 87.8°F (31°C).

What is the least humid month in Antioch?

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

What is the average humidity in September in Antioch?

The average relative humidity in September in Antioch is 52%.

How many days does it rain in September in Antioch?

In September, in Antioch, the rain falls for 1.3 days. Throughout September, 0.08" (2mm) of precipitation is accumulated.

When it does not snow in Antioch?

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

How many hours of daylight does Antioch have in September?

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

When are sunrise and sunset in September in Antioch?

On the first day of September in Antioch, California, 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?

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

What is the UV index reading in September in Antioch?

In Antioch, the average daily maximum UV index in September is 5. A UV Index value of 3 to 5 symbolizes a moderate health threat from unprotected exposure to UV radiation.
Average humidity
Average rainfall days
Average snowfall days
Average daylight
Average sunshine
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).

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).

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).

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%).

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").

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).

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).

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 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: 11h and 1min

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).

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).

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).

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).

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).

Antioch, California, USA

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