September weather forecast
Winnetka, CA

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Weather in September

The first month of the autumn, September, is also a moderately hot month in Winnetka, California, with an average temperature varying between 63°F and 83.1°F.

Temperature

Winnetka records an average high-temperature of a still warm 83.1°F as September arrives, nearly mirroring the previous month's climate. The nights of September in Winnetka anticipate an average low-temperature of 63°F.

Heat index

The average heat index in September is computed to be 84.2°F. Enduring exposure and continuous activity might cause a feeling of tiredness and induce heat cramps.
It is noted that heat index values are ascertained for locations in the shade and with gentle breezes. Exposure to the direct sun might augment heat index values by 15 Fahrenheit (8 Celsius) degrees.
Note: The heat index, also known as 'apparent temperature' or 'real feel', is a single figure representing how weather conditions feel when combining temperature and humidity. One's perception of temperature can vary depending on physical activity and individual heat sensitivity, influenced by factors like wind, attire, and metabolic variations. 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 particularly relevant to babies and toddlers. Young ones often do not realize the necessity to rest and replenish their fluids. Thirst is a delayed indication of dehydration - keeping hydrated, particularly in prolonged physical activity, is crucial.

Humidity

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

Rainfall

In Winnetka, in September, it is raining for 2.6 days, with typically 0.16" of accumulated precipitation. Throughout the year, there are 42.7 rainfall days, and 6.46" of precipitation is accumulated.

Snowfall

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

Daylight

In September, the average length of the day in Winnetka, California, is 12h and 22min.
On the first day of the month, sunrise is at 6:27 am and sunset at 7:20 pm. On the last day of September, sunrise is at 6:48 am and sunset at 6:40 pm PDT.

Sunshine

In Winnetka, the average sunshine in September is 10.8h.

UV index

June through September, with an average maximum UV index of 6, are months with the highest UV index in Winnetka. A UV Index value of 6 to 7 symbolizes a high health vulnerability from exposure to the Sun's UV rays for the average person.
Note: In September, a regular UV index of 6 translates into these guidelines:
Prevent overexposure. Protection from the sun's harmful effects is needed. Make an effort to avoid direct sun exposure between 10 a.m. and 4 p.m., the peak period for UV radiation, and note that objects like parasols or canopies might not offer full sun protection. Sun protection is enhanced with clothing that boasts a tight weave yet offers a loose fit.
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FAQ

How hot is September in Winnetka?

September temperatures in Winnetka vary between a high-temperature of 83.1°F and a low-temperature of 63°F. The average heat index (a.k.a. 'real feel', 'feels like'), which takes the relative humidity and factors it into the air temperature reading, in September is computed to be 84.2°F.

What is the average humidity in September in Winnetka?

In Winnetka, California, the average relative humidity in September is 52%.

How many days does it rain in September in Winnetka?

In Winnetka, California, during September, the rain falls for 2.6 days and regularly aggregates up to 0.16" of precipitation.

When it does not snow in Winnetka?

January through November are months without snowfall in Winnetka.

What is the average length of the day in September in Winnetka?

In Winnetka, the average day length in September is 12h and 22min.

When are sunrise and sunset in September in Winnetka?

In September, on the first day of the month, sunrise is at 6:27 am and sunset at 7:20 pm. On the last day of the month, in Winnetka, sunrise is at 6:48 am and sunset at 6:40 pm PDT.

How many hours of sunshine does Winnetka have in September?

In Winnetka, California, the average sunshine duration in September is 10.8h.

What are the months with the highest UV index in Winnetka?

The months with the highest UV index in Winnetka are June through September, with an average maximum UV index of 6.

What is the UV index intensity in September in Winnetka?

The average daily maximum UV index in September is 6. A UV Index reading of 6 to 7 represents a high health vulnerability from unsafe exposure to Sun's UV rays.
Average high temperature
Average low temperature
Average pressure
Average wind speed
Average max. wind speed
Average wind speed gusts
Average humidity
Average rainfall
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
Winnetka, CA

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).

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Average pressure in September
Winnetka, CA

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).

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Average wind speed in September
Winnetka, CA

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).

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Average humidity in September
Winnetka, CA

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%).

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Average rainfall in September
Winnetka, CA

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").

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Average rainfall days in September
Winnetka, CA

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).

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Average snowfall days in September
Winnetka, CA

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).

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

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

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 5min

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).

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Average sunshine days in September
Winnetka, CA

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).

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Average UV index in September
Winnetka, CA

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).

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Average cloud cover in September
Winnetka, CA

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).

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Average visibility in September
Winnetka, CA

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).

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Winnetka, California, USA

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