September weather forecast
Chico, CA

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Dense forest and a bridge crossing over the famed Big Chico Creek located in the Bidwell Park in Chico, California
Dense forest and a bridge crossing over the famed Big Chico Creek located in the Bidwell Park in Chico, California

Weather in September

September, the first month of the autumn in Chico, is still a tropical month, with temperature in the range of an average high of 87.4°F (30.8°C) and an average low of 59.9°F (15.5°C).

Temperature

September's arrival comes with a mild decrease in the average high-temperature, moving subtly from a hot 93.4°F (34.1°C) in August to a still tropical 87.4°F (30.8°C). Significant variation from daytime temperatures marks September, with the month recording a nightly average of 59.9°F (15.5°C).

Humidity

In September, the average relative humidity is 35%.

Rainfall

In September, the rain falls for 3.2 days. Throughout September, 0.35" (9mm) of precipitation is accumulated. Throughout the year, in Chico, there are 90.7 rainfall days, and 21.81" (554mm) of precipitation is accumulated.

Snowfall

January through November are months without snowfall.

Daylight

In September, the average length of the day in Chico is 12h and 26min.
On the first day of September, sunrise is at 6:36 am and sunset at 7:37 pm. On the last day of the month, sunrise is at 7:03 am and sunset at 6:50 pm PDT.

Sunshine

The average sunshine in September is 11.1h.

UV index

The average daily maximum UV index in September in Chico is 5. A UV Index estimate of 3 to 5 represents a medium vulnerability from unsafe exposure to UV radiation for average individuals.
Note: An average UV index of 5 in September transforms into this advice:
Be careful. Light complexion individuals might get burns in fewer than 30 minutes. The midday Sun can be dangerous due to its intense radiation; always find shade and reduce exposure. Always opt for UVA and UVB-resistant sunglasses on radiant days.
Updated: Aug 26, 2024
Published by: Weather U.S. | About Us
Data Sources | Weather Forecasting & Climate

Frequently asked questions

How hot is September?

Chico in September has an average high-temperature of 87.4°F (30.8°C) and an average low-temperature of 59.9°F (15.5°C). The average heat index (a.k.a. 'real feel', 'apparent temperature'), which factors the actual air temperature with the relative humidity, in June is evaluated at 87.8°F (31°C).

What is the average humidity in September?

In September, the average relative humidity is 35%.

How much does it rain in September?

In Chico, in September, during 3.2 rainfall days, 0.35" (9mm) of precipitation is typically accumulated.

When it does not snow?

January through November are months without snowfall.

How many hours of daylight does Chico have in September?

The average day length in September is 12h and 26min.

What time are sunrise and sunset in September in Chico?

On the first day of September, sunrise is at 6:36 am and sunset at 7:37 pm. On the last day of the month, sunrise is at 7:03 am and sunset at 6:50 pm PDT.

How long on average sun shines in September?

In Chico, California, the average sunshine duration in September is 11.1h.

What is the UV index intensity in September?

The average daily maximum UV index in September is 5. A UV Index reading of 3 to 5 represents a moderate health threat from exposure to the Sun's UV radiation.
Average humidity
Average rainfall days
Average snowfall
Average snowfall days
Average daylight
Average sunshine
Average sunshine days
Average UV index
Average cloud cover
Average visibility

Average temperature in September
Chico, CA

Average temperature in September - Chico, CA
  • Average high temperature in September: 87.4°F

The warmest month (with the highest average high temperature) is July (95.2°F).
The month with the lowest average high temperature is December (53.2°F).

  • Average low temperature in September: 59.9°F

The month with the highest average low temperature is July (63.5°F).
The coldest month (with the lowest average low temperature) is December (39°F).

Average pressure in September
Chico, CA

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

The month with the highest atmospheric pressure is January (30.16"Hg).
The month with the lowest atmospheric pressure is June (29.9"Hg).

Average wind speed in September
Chico, CA

Average wind speed in September - Chico, CA
  • Average wind speed in September: 5.3mph

The windiest month (with the highest average wind speed) is March (6.8mph).
The calmest month (with the lowest average wind speed) is August (4.9mph).

Average humidity in September
Chico, CA

Average humidity in September - Chico, CA
  • Average humidity in September: 35%

The month with the highest relative humidity is March (72%).
The month with the lowest relative humidity is July (32%).

Average rainfall in September
Chico, CA

Average rainfall in September - Chico, CA
  • Average rainfall in September: 0.35"

The wettest month (with the highest rainfall) is February (3.94").
The driest month (with the least rainfall) is July (0.08").

Average rainfall days in September
Chico, CA

Average rainfall days in September - Chico, CA
  • Average rainfall days in September: 3.2 days

The month with the highest number of rainy days is March (15.2 days).
The month with the least rainy days is August (1.9 days).

Average snowfall in September
Chico, CA

Average snowfall in September - Chico, CA
  • Average snowfall in September: 0"

The month with the highest snowfall is December (0.12").
The months with the least snowfall are January, February, March, April, May, June, July, August, September, October and November (0").

Average snowfall days in September
Chico, CA

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

The month with the highest number of snowfall days is December (0.4 days).
The months with the least snowfall days are January, March, April, May, June, July, August, September, October and November (0 days).

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

Average daylight in September / Average sunshine in September - Chico, CA
  • Average daylight in September: 12h and 2min

The month with the longest days is June (Average daylight: 14h and 54min).
The month with the shortest days is December (Average daylight: 9h and 24min).

  • Average sunshine in September: 11h and 1min

The month with the most sunshine is July (Average sunshine: 12h and 12min).
The months with the least sunshine are January and December (Average sunshine: 5h and 54min).

Average sunshine days in September
Chico, CA

Average sunshine days in September - Chico, CA
  • Average sunshine days in September: 25.5 days

The month with the most sunshine days is August (28.1 days).
The month with the least sunshine days is March (14.9 days).

Average UV index in September
Chico, CA

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

The months with the highest UV index are June and July (UV index 7).
The months with the lowest UV index are January, February, November and December (UV index 3).

Average cloud cover in September
Chico, CA

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

The month with the most cloud cover is March (Cloud cover 38).
The month with the least cloud cover is July (Cloud cover 4).

Average visibility in September
Chico, CA

Average visibility in September - Chico, 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).

Chico, California, USA

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