September weather forecast and climate
Whittier, CA

Weather in September

September, the first month of the autumn, in Whittier, is still a warm month, with average temperature varying between 85.1°F (29.5°C) and 64.8°F (18.2°C).

Temperature

In Whittier, the average high-temperature in September is practically the same as in August - a moderately hot 85.1°F (29.5°C). In Whittier, the average low-temperature is 64.8°F (18.2°C).

Heat index

In September, the average heat index is appraised at a hot 87.4°F (30.8°C). Constant exposure and activity lead to possible fatigue. Prolonged exercise may result in heat cramps.
Take into consideration that the heat index values are calculated for shade and light wind conditions. Exposure to direct sunshine can increase heat index values by up to 15 Fahrenheit (8 Celsius) degrees.
Note: The heat index, also known as 'apparent temperature', 'feels like', 'real feel', or 'felt air temperature', combines air temperature and relative humidity to represent a human perceived temperature equivalent. This effect is individual, with diverse people perceiving weather differently for numerous reasons (metabolic differences, wind, clothing), and activity. Be aware that direct exposure to sunlight increases heat impact, and may raise the heat index additionally, by up to 15 Fahrenheit (8 Celsius) degrees. Heat index values are especially crucial for babies and toddlers. Children are often less aware of the need to rest and re-hydrate. Thirst is a late sign of dehydration - it is vital to remain hydrated, particularly during prolonged physical activities.

Humidity

In September, the average relative humidity is 53%.

Rainfall

In September, the rain falls for 2.3 days. Throughout September, 0.08" (2mm) of precipitation is accumulated. Throughout the year, in Whittier, there are 38.2 rainfall days, and 5.28" (134mm) of precipitation is accumulated.

Daylight

The average length of the day in Whittier is 12.4h.

Sunshine

The average sunshine in Whittier is 10.6h.

UV index

In Whittier, the average daily maximum UV index in September is 6. A UV Index value of 6 to 7 symbolizes a high health risk from the exposure to the Sun's UV rays for ordinary individuals.
Note: The average daily UV index of 6 in September transform into the following instructions:
Take precautions against overexposure. Protection against sun damage is needed. The Sun's UV radiation is most powerful between 10 a.m. and 4 p.m. To the extent possible, limit exposure to the direct sun during these hours. A wide-brim hat offers excellent sun protection for eyes, ears, face, and neck. Sunglasses with UVA and UVB protection significantly reduce eye damage from sun exposure. Tightly woven, loose-fitting clothes provide additional protection from the Sun.
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FAQ

What is the temperature in September in Whittier?

In Whittier, in September, the average high-temperature is 85.1°F (29.5°C), and the average low-temperature is 64.8°F (18.2°C). The average heat index (a.k.a. 'feels like', 'felt air temperature'), that calculates temperature value influenced by the moisture in the air, in September is estimated at 87.4°F (30.8°C).

What is the average humidity in September in Whittier?

The average relative humidity in September in Whittier, California, is 53%.

How much does it rain in Whittier in September?

In Whittier, California, during September, the rain falls for 2.3 days and regularly aggregates up to 0.08" (2mm) of precipitation.

How many hours of daylight does Whittier have in September?

The average length of the day in September in Whittier is 12.4h.

How many hours of sunshine does Whittier have in September?

In Whittier, California, the average sunshine in September is 10.6h.

What is the UV index intensity in September in Whittier?

The average daily maximum UV index in September in Whittier is 6. A UV Index estimate of 6 to 7 represents a high health risk from the exposure to the Sun's UV radiation.

Average temperature in September
Whittier, CA

Average temperature in September - Whittier, CA
  • Average high temperature in September: 85.1°F

The warmest month (with the highest average high temperature) is August (86.5°F).
The month with the lowest average high temperature is December (64.9°F).

  • Average low temperature in September: 64.8°F

The month with the highest average low temperature is August (65.8°F).
The coldest month (with the lowest average low temperature) is February (49.8°F).

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Average pressure in September
Whittier, CA

Average pressure in September - Whittier, CA
  • Average pressure in September: 29.89"

The month with the highest atmospheric pressure is January (30.1").
The month with the lowest atmospheric pressure is June (29.88").

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Average wind speed in September
Whittier, CA

Average wind speed in September - Whittier, CA
  • Average wind speed in September: 4.7mph

The windiest month (with the highest average wind speed) is April (6mph).
The calmest months (with the lowest average wind speed) are September and October (4.7mph).

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Average humidity in September
Whittier, CA

Average humidity in September - Whittier, CA
  • Average humidity in September: 53%

The month with the highest relative humidity is June (62%).
The month with the lowest relative humidity is November (47%).

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Average rainfall in September
Whittier, CA

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

The wettest month (with the highest rainfall) is December (1.14").
The driest month (with the least rainfall) is June (0.04").

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Average rainfall days in September
Whittier, CA

Average rainfall days in September - Whittier, CA
  • Average rainfall days in September: 2.3 days

The month with the highest number of rainy days is March (5.1 days).
The month with the least rainy days is June (1 days).

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

Average daylight in September / Average sunshine in September - Whittier, CA
  • Average daylight in September: 12.4h

The month with the longest days is June (Average daylight: 14.4h).
The month with the shortest days is December (Average daylight: 9.9h).

  • Average sunshine in September: 10.6h

Months with the most sunshine are July and August (Average sunshine: 12h).
The month with the least sunshine is February (Average sunshine: 6.7h).

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Average sunshine days in September
Whittier, CA

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

The month with the most sunshine days is June (27.9 days).
The month with the least sunshine days is February (22.6 days).

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Average UV index in September
Whittier, CA

Average UV index in September - Whittier, CA
  • Average UV index in September: 6

The month with the highest UV index is August (UV index 7).
Months with the lowest UV index are February, November and December (UV index 4).

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Average cloud cover in September
Whittier, CA

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

Months with the most cloud cover are March and December (Cloud cover 22).
The month with the least cloud cover is August (Cloud cover 6).

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Average visibility in September
Whittier, CA

Average visibility in September - Whittier, CA
  • Average visibility in September: 6mi

Months with the highest visibility are January, February, March, April, May, June, July, August, September, October, November and December (6mi).
Months with the lowest visibility are January, February, March, April, May, June, July, August, September, October, November and December (6mi).

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