September weather forecastAugust, CA
September
Weather in September
September, the first month of the autumn in August, is still a hot month, with an average temperature ranging between min 58.8°F (14.9°C) and max 88.7°F (31.5°C).Temperature
August experiences a subtle adjustment in high-temperatures to a still hot 88.7°F (31.5°C) with the onset of September, maintaining near parity with August's 93°F (33.9°C). August demonstrates a significant disparity from daytime highs throughout the month of September, with an average nighttime temperature of 58.8°F (14.9°C).Heat index
During September, the heat index is estimated at a hot 91.4°F (33°C). Implement additional cautionary measures, heat cramps and heat exhaustion could occur. Prolonged activity might induce heatstroke.In terms of the heat index, values are set with light wind and shade conditions in mind. If exposed to direct sunlight, the heat index could climb by up to 15 Fahrenheit (8 Celsius) degrees.
Note: The heat index, also known as 'apparent temperature' or 'felt air temperature', joins air temperature with relative humidity to produce a temperature perception for humans. Factors including metabolic differences, physical activity, and clothing are additional elements that influence the individual's temperature experience. Consider that direct sun exposure can intensify the felt heat, adding potentially 15 Fahrenheit (8 Celsius) degrees to the heat index. Heat index values are especially vital to 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
In August, 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. In August, during the entire year, the rain falls for 64.2 days and collects up to 11.34" (288mm) of precipitation.Snowfall
January through November are months without snowfall.Daylight
The average length of the day in September is 12h and 25min.On the first day of the month, sunrise is at 6:35 am and sunset at 7:33 pm. On the last day of September, sunrise is at 7:00 am and sunset at 6:48 pm PDT.
Sunshine
In September, the average sunshine is 11.4h.UV index
The average daily maximum UV index in September is 5. A UV Index value of 3 to 5 symbolizes a medium vulnerability from unsafe exposure to UV radiation for average individuals.Note: The maximum daily UV index of 5 during September translates into the following directions:
Exercise care. People with light skin might get burns in fewer than 30 minutes. Direct exposure to the Sun's intense radiation around midday should be avoided for health reasons. Wearing sunglasses with both UVA and UVB protection effectively reduces sun-induced eye damage.
Published by: Weather U.S. | About Us
Data Sources | Weather Forecasting & Climate
Frequently asked questions
Average temperature in September
August, 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
August, 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
August, 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
August, 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
August, 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
August, 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
August, 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
August, CA
- Average daylight in September: 12h and 24min
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 24min
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
August, 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
August, 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
August, 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
August, 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).
