September weather forecast
Montclair, CA

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Weather in September

The first month of the autumn, September, is still a tropical month in Montclair, California, with temperature in the range of an average low of 63.5°F and an average high of 88.2°F.

Temperature

September brings an average high-temperature of a still hot 88.2°F, nearly identical to the preceding month. Montclair documents a substantial deviation from daytime highs with a consistent low-temperature of 63.5°F during September nights.

Heat index

The heat index value for September is estimated at a hot 89.6°F. If one remains active during constant exposure, it might cause exhaustion and heat cramps.
When considering the heat index, it's pivotal to note it is for shade and mild wind conditions. The heat index could see an increase by 15 Fahrenheit (8 Celsius) degrees under direct sunshine.
Note: The heat index, also known as 'felt air temperature' or 'apparent temperature', blends air temperature and moisture content to represent the felt temperature to humans. One's perception of weather can be shaped by other factors, involving metabolic differences, pregnancy, and physical exertion. One should be aware that direct sunshine can amplify the perceived temperature, raising the heat index by as much as 15 Fahrenheit (8 Celsius) degrees. Heat index values are largely significant for babies and toddlers. Young ones often disregard the necessity to rest and hydrate. Thirst usually indicates advanced dehydration - hence, it is key to stay hydrated, particularly during ongoing physical activities.

Humidity

In Montclair, the average relative humidity in September is 44%.

Rainfall

In Montclair, during September, the rain falls for 2.5 days and regularly aggregates up to 0.12" of precipitation. In Montclair, during the entire year, the rain falls for 49.6 days and collects up to 7.8" of precipitation.

Snowfall

In Montclair, California, snow does not fall in January, March through December.

Daylight

The average length of the day in September is 12h and 22min.
On the first day of the month, sunrise is at 6:24 am and sunset at 7:17 pm. On the last day of September, sunrise is at 6:44 am and sunset at 6:36 pm PDT.

Sunshine

In Montclair, the average sunshine in September is 10.7h.

UV index

The average daily maximum UV index in September in Montclair is 6. A UV Index of 6 to 7 symbolizes a high health hazard from unsafe exposure to UV radiation for ordinary individuals.
Note: The maximum daily UV index, 6 in September, converts into the following recommendations:
Deflect overexposure. Sun protection is a necessity. Stay out of direct sunlight and seek shade between 10 a.m. and 4 p.m., when UV radiation is strongest, but remember that shade devices may not offer full sun protection. Sunglasses that ward off UVA and UVB rays play a pivotal role in reducing solar eye damage.
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FAQ

How hot does it get in Montclair in September?

September temperatures vary between a high-temperature of 88.2°F and a low-temperature of 63.5°F. The average heat index (a.k.a. 'apparent temperature', 'feels like'), which represents the influence of relative humidity on air temperature, in September is estimated at 89.6°F.

What is the average humidity in September in Montclair?

In Montclair, the average relative humidity in September is 44%.

How many days does it rain in September in Montclair?

In September, in Montclair, the rain falls for 2.5 days. Throughout September, 0.12" of precipitation is accumulated.

When it does not snow in Montclair?

In Montclair, California, snow does not fall in January, March through December.

How many hours of daylight does Montclair have in September?

The average day length in September is 12h and 22min.

When are sunrise and sunset in September in Montclair?

On the first day of September in Montclair, California, sunrise is at 6:24 am and sunset at 7:17 pm. On the last day of the month, sunrise is at 6:44 am and sunset at 6:36 pm PDT.

How many hours of sunshine does Montclair have in September?

The average sunshine duration in September in Montclair is 10.7h.

What is the UV index intensity in September in Montclair?

In September, the average daily maximum UV index in Montclair is 6. A UV Index reading of 6 to 7 represents a high health threat 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
Montclair, CA

Average temperature in September - Montclair, CA
  • Average high temperature in September: 88.2°F

The warmest month (with the highest average high temperature) is August (91°F).
The month with the lowest average high temperature is December (62.1°F).

  • Average low temperature in September: 63.5°F

The month with the highest average low temperature is August (65.8°F).
The coldest month (with the lowest average low temperature) is December (45.5°F).

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Average pressure in September
Montclair, CA

Average pressure in September - Montclair, CA
  • Average pressure in September: 29.88"Hg

The month with the highest atmospheric pressure is January (30.1"Hg).
The month with the lowest atmospheric pressure is June (29.86"Hg).

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Average wind speed in September
Montclair, CA

Average wind speed in September - Montclair, CA
  • Average wind speed in September: 4.4mph

The windiest months (with the highest average wind speed) are April and May (5.8mph).
The calmest month (with the lowest average wind speed) is September (4.4mph).

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Average humidity in September
Montclair, CA

Average humidity in September - Montclair, CA
  • Average humidity in September: 44%

The months with the highest relative humidity are March and May (54%).
The month with the lowest relative humidity is August (42%).

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Average rainfall in September
Montclair, CA

Average rainfall in September - Montclair, CA
  • Average rainfall in September: 0.12"

The wettest month (with the highest rainfall) is February (1.77").
The driest month (with the least rainfall) is June (0.04").

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Average rainfall days in September
Montclair, CA

Average rainfall days in September - Montclair, CA
  • Average rainfall days in September: 2.5 days

The month with the highest number of rainy days is March (7.1 days).
The month with the least rainy days is June (1.2 days).

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Average snowfall days in September
Montclair, CA

Average snowfall days in September - Montclair, CA
  • Average snowfall days in September: 0 days

The month with the highest number of snowfall days is February (0.1 days).
The months with the least snowfall days are January, March, April, May, June, July, August, September, October, November and December (0 days).

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

Average daylight in September / Average sunshine in September - Montclair, 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 4min

The month with the most sunshine is July (Average sunshine: 12h and 6min).
The months with the least sunshine are February and December (Average sunshine: 6h and 54min).

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Average sunshine days in September
Montclair, CA

Average sunshine days in September - Montclair, CA
  • Average sunshine days in September: 25.4 days

The month with the most sunshine days is June (28.2 days).
The month with the least sunshine days is February (21.5 days).

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Average UV index in September
Montclair, CA

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

The months with the highest UV index are July and August (UV index 7).
The month with the lowest UV index is December (UV index 3).

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Average cloud cover in September
Montclair, CA

Average cloud cover in September - Montclair, CA
  • Average cloud cover in September: 6

The month with the most cloud cover is December (Cloud cover 21).
The month with the least cloud cover is August (Cloud cover 5).

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Average visibility in September
Montclair, CA

Average visibility in September - Montclair, 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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Montclair, California, USA

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