September weather forecast
Stockton, CA

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Weather in September

With the advent of September, Stockton begins to transition from summer to autumn. An influx of moisture can be observed in the weather as rainfall increases to 0.08" (2mm) from no precipitation in August. While temperatures start to decrease, September retains a sizeable amount of sunshine. Moving into October, September paves the way for cooler temperatures, increased rainfall, and reduced sunshine hours.

Temperature

With the arrival of September, Stockton's average high-temperature registers at a still hot 88.7°F (31.5°C), indicating a subtle variation from the previous month. During September, Stockton's temperature records a considerable difference from its daily highs to an average low of 58.8°F (14.9°C).

Heat index

Throughout September, the heat index is appraised at a tropical 91.4°F (33°C). Incorporate additional safety actions, heat cramps and heat exhaustion are possible. Long-term activity may induce heatstroke.
It is essential to grasp that the heat index's numbers are for shade and light wind settings. Direct exposure to sunshine could lead to a heat index increase by 15 Fahrenheit (8 Celsius) degrees.
Note: The heat index, also known as 'felt air temperature' or 'feels like', is an indicator that blends the effects of temperature and humidity to depict perceived warmth. One's weather perception can be influenced by a range of factors including metabolic differences, being pregnant, and their level of physical activity. When exposed to direct sunlight, it's possible for the heat index to increase by as much as 15 Fahrenheit (8 Celsius) degrees. Heat index values are extremely significant for children. Young ones are generally more prone to risk than adults due to their reduced ability to sweat. Their large skin surface area relative to their diminutive bodies and elevated heat production from their activities further enhance this risk.

Humidity

The average relative humidity in September is 46%.

Rainfall

January through July, September through December are months with rainfall. September is the first month it rains. Throughout September, in the average 1.6 rainfall days, it receives 0.08" (2mm) of precipitation. Throughout the year, in Stockton, there are 64.2 rainfall days, and 11.34" (288mm) of precipitation is accumulated.

Snowfall

January through November are months without snowfall in Stockton.

Daylight

In September, the average length of the day is 12h and 25min.
On the first day of the month, sunrise is at 6:35 am and sunset at 7:34 pm. On the last day of September, sunrise is at 7:00 am and sunset at 6:49 pm PDT.

Sunshine

In Stockton, the average sunshine in September is 11.4h.

UV index

The average daily maximum UV index in September is 5. A UV Index reading of 3 to 5 represents a moderate threat to health from unprotected exposure to Sun's UV rays for ordinary individuals.
Note: In September, the maximum UV index of 5 transforms into these recommendations:
Exercise prevention - Precautions against solar damage are endorsed. It's recommended to limit sun exposure when its radiation is at its peak during midday. Shield yourself from the harmful effects of UV radiation with sun-protective attire, a hat, and quality sunglasses.
Updated: Aug 13, 2024
Published by: Weather U.S. | About Us
Data Sources | Weather Forecasting & Climate

Frequently asked questions

How hot is it in September?

In September, the average high-temperature and low-temperature are 88.7°F (31.5°C) and 58.8°F (14.9°C) respectively. The average heat index (a.k.a. 'real feel', 'apparent temperature'), which factors the actual air temperature with the relative humidity, in September is appraised at 91.4°F (33°C).

What is the average humidity in September?

The average relative humidity in September is 46%.

When does it start raining?

September is the first month it rains. Throughout September, in the average 1.6 rainfall days, it receives 0.08" (2mm) of precipitation.

When it does not snow?

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

What is the average length of the day in September?

The average day length in September in Stockton is 12h and 25min.

When is the sunrise / sunset in September?

In September, on the first day of the month, sunrise is at 6:35 am and sunset at 7:34 pm. On the last day of the month, sunrise is at 7:00 am and sunset at 6:49 pm PDT.

How long on average sun shines in September?

In Stockton, the average sunshine duration in September is 11.4h.

What is the UV index intensity in September?

In Stockton, the average daily maximum UV index in September is 5. A UV Index value of 3 to 5 symbolizes a medium health risk from unsafe exposure to Sun's UV rays.
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
Stockton, CA

Average temperature in September - Stockton, CA
  • Average high temperature in September: 88.7°F

The warmest month (with the highest average high temperature) is July (94.3°F).
The month with the lowest average high temperature is December (55.2°F).

  • Average low temperature in September: 58.8°F

The month with the highest average low temperature is August (59.5°F).
The coldest month (with the lowest average low temperature) is December (41.2°F).

Average pressure in September
Stockton, CA

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

The month with the highest atmospheric pressure is January (30.15"Hg).
The month with the lowest atmospheric pressure is June (29.91"Hg).

Average wind speed in September
Stockton, CA

Average wind speed in September - Stockton, CA
  • Average wind speed in September: 5.8mph

The windiest month (with the highest average wind speed) is June (7.1mph).
The calmest month (with the lowest average wind speed) is November (4.7mph).

Average humidity in September
Stockton, CA

Average humidity in September - Stockton, CA
  • Average humidity in September: 46%

The month with the highest relative humidity is January (73%).
The month with the lowest relative humidity is July (44%).

Average rainfall in September
Stockton, CA

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

The wettest month (with the highest rainfall) is February (2.13").
The driest month (with the least rainfall) is August (0").

Average rainfall days in September
Stockton, CA

Average rainfall days in September - Stockton, CA
  • Average rainfall days in September: 1.6 days

The month with the highest number of rainy days is March (12 days).
The month with the least rainy days is August (0.7 days).

Average snowfall days in September
Stockton, CA

Average snowfall days in September - Stockton, 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
Stockton, CA

Average daylight in September / Average sunshine in September - Stockton, 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 2min

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

Average sunshine days in September
Stockton, CA

Average sunshine days in September - Stockton, CA
  • Average sunshine days in September: 28 days

The month with the most sunshine days is August (30.2 days).
The month with the least sunshine days is March (17.8 days).

Average UV index in September
Stockton, CA

Average UV index in September - Stockton, 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
Stockton, CA

Average cloud cover in September - Stockton, CA
  • Average cloud cover in September: 7

The month with the most cloud cover is March (Cloud cover 35).
The month with the least cloud cover is July (Cloud cover 4).

Average visibility in September
Stockton, CA

Average visibility in September - Stockton, 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).

Stockton, California, USA

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