September weather forecastWinnetka, CA
September
Weather in September
The first month of the autumn, September, is still a warm month in Winnetka, California, with an average temperature ranging between max 83.1°F (28.4°C) and min 63°F (17.2°C).Temperature
Winnetka experiences an average high-temperature of a still warm 83.1°F (28.4°C) in September, marking an insignificant shift from 85.6°F (29.8°C) in August. During the month of September, the temperature in Winnetka, California, generally drops to a low average of 63°F (17.2°C).Heat index
The average heat index in September is calculated to be 84.2°F (29°C). With extended exposure and activity, one might feel exhausted and experience heat cramps.For clarity, heat index numbers account for light winds and areas under shade. When under direct sunshine, the heat index may be elevated by 15 Fahrenheit (8 Celsius) degrees.
Note: The heat index, also known as 'apparent temperature' or 'felt air temperature', is a composite of temperature and humidity figures to convey how warm it feels. Elements such as metabolic variations, pregnancy, and physical exertion can shape one's weather perception. Remember, direct sunlight exposure can heighten the heat impact and might increase the heat index by 15 Fahrenheit (8 Celsius) degrees. Heat index values are especially vital to children. Youths are typically more endangered than adults since they usually sweat less. Their larger skin surface concerning their smaller bodies and higher heat production due to activity further adds to their vulnerability.
Humidity
The average relative humidity in September is 52%.Rainfall
In Winnetka, in September, during 2.6 rainfall days, 0.16" (4mm) of precipitation is typically accumulated. In Winnetka, during the entire year, the rain falls for 42.7 days and collects up to 6.46" (164mm) of precipitation.Snowfall
In Winnetka, California, snow does not fall in January through November.Daylight
In Winnetka, the average length of the day in September is 12h and 22min.On the first day of September, sunrise is at 6:28 am and sunset at 7:19 pm. On the last day of the month, sunrise is at 6:48 am and sunset at 6:39 pm PDT.
Sunshine
In September, the average sunshine is 10.8h.UV index
June through September, with an average maximum UV index of 6, are months with the highest UV index. A UV Index estimate of 6 to 7 represents a high health vulnerability from exposure to the Sun's UV rays for average individuals.Note: During September, 6 as the daily maximum UV index converts into the following advice:
Ward off overexposure. Defence against solar harm is crucial. The Sun's UV radiation is most potent between 10 a.m. and 4 p.m. Try to limit direct exposure to the Sun during this period. A hat with a broad brim is indispensable, filtering out up to half of UV rays.
Published by: Weather U.S. | About Us
Data Sources | Weather Forecasting & Climate
Frequently asked questions
Average temperature in September
Winnetka, CA
- Average high temperature in September: 83.1°F
The warmest month (with the highest average high temperature) is August (85.6°F).
The month with the lowest average high temperature is December (61.9°F).
- Average low temperature in September: 63°F
The month with the highest average low temperature is August (64.8°F).
The coldest month (with the lowest average low temperature) is December (46.9°F).
Average pressure in September
Winnetka, CA
- Average pressure in September: 29.9"Hg
The month with the highest atmospheric pressure is January (30.11"Hg).
The month with the lowest atmospheric pressure is June (29.89"Hg).
Average wind speed in September
Winnetka, CA
- Average wind speed in September: 4.5mph
The windiest months (with the highest average wind speed) are January and December (6.1mph).
The calmest month (with the lowest average wind speed) is September (4.5mph).
Average humidity in September
Winnetka, CA
- Average humidity in September: 52%
The month with the highest relative humidity is June (59%).
The month with the lowest relative humidity is November (47%).
Average rainfall in September
Winnetka, CA
- Average rainfall in September: 0.16"
The wettest month (with the highest rainfall) is February (1.22").
The driest month (with the least rainfall) is June (0.04").
Average rainfall days in September
Winnetka, CA
- Average rainfall days in September: 2.6 days
The month with the highest number of rainy days is March (6.5 days).
The month with the least rainy days is June (1.4 days).
Average snowfall days in September
Winnetka, 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
Winnetka, CA
- Average daylight in September: 12h and 24min
The month with the longest days is June (Average daylight: 14h and 24min).
The month with the shortest days is December (Average daylight: 9h and 54min).
- Average sunshine in September: 10h and 48min
The months with the most sunshine are June and July (Average sunshine: 12h and 6min).
The months with the least sunshine are January, February and December (Average sunshine: 6h and 48min).
Average sunshine days in September
Winnetka, CA
- Average sunshine days in September: 25.5 days
The months with the most sunshine days are August and October (27.3 days).
The month with the least sunshine days is February (22 days).
Average UV index in September
Winnetka, CA
- Average UV index in September: 6
The months with the highest UV index are June, July, August and September (UV index 6).
The month with the lowest UV index is December (UV index 3).
Average cloud cover in September
Winnetka, CA
- Average cloud cover in September: 7
The month with the most cloud cover is March (Cloud cover 22).
The month with the least cloud cover is August (Cloud cover 4).
Average visibility in September
Winnetka, 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).
