September weather forecast
Rancho Cucamonga, CA

Weather in September

September, the first month of the autumn in Rancho Cucamonga, is also a hot month, with an average temperature ranging between max 88.3°F (31.3°C) and min 63.7°F (17.6°C).

Temperature

In Rancho Cucamonga, the average high-temperature in September is almost the same as in August - a still hot 88.3°F (31.3°C). The average low-temperature, in Rancho Cucamonga, is 63.7°F (17.6°C).

Heat index

The average heat index in September is computed to be a tropical 89.2°F (31.8°C). Exhaustion is likely with prolonged exposure and activity. Sustaining activity may result in heat cramps.
Note that heat index values are valued for light wind and location in the shade. Exposure to direct sunshine can increase heat index values by up to 15 Fahrenheit (8 Celsius) degrees.
Note: The heat index, also known as 'feels like', 'apparent temperature', 'real feel', or 'felt air temperature', is an index that combines air temperature and relative humidity to determine the human-perceived temperature equivalent. This effect is individual, with diverse people perceiving weather differently for numerous reasons (metabolic differences, differences in body mass, height, and shape, pregnancy), and activity. Bear in mind that direct sunshine exposure increases weather impact, and may raise heat index by up to 15 Fahrenheit (8 Celsius) degrees. Heat index values are especially crucial for babies and toddlers. Young children are generally more endangered than adults, as they usually less sweat. And also, due to larger skin surface relative to their small bodies and higher heat production as a result of their activity.

Humidity

In September, the average relative humidity in Rancho Cucamonga is 43%.

Rainfall

In Rancho Cucamonga, in September, during 1.8 rainfall days, 0.08" (2mm) of precipitation is typically accumulated. In Rancho Cucamonga, during the entire year, the rain falls for 42.3 days and collects up to 4.53" (115mm) of precipitation.

Snowfall

In Rancho Cucamonga, 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 7:16 pm. On the last day of September, in Rancho Cucamonga, sunrise is at 6:44 am and sunset at 6:36 pm PDT.

Sunshine

In September, the average sunshine in Rancho Cucamonga is 10.7h.

UV index

In Rancho Cucamonga, the average daily maximum UV index in September is 6. A UV Index value of 6 to 7 symbolizes a high health hazard from exposure to the Sun's UV radiation for the ordinary person.
Note: The average daily UV index of 6 in September transform into the following instructions:
Take precautions against overexposure. Fair-skinned people may get burned in less than 20 minutes. 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 the 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 Rancho Cucamonga?

In September, in Rancho Cucamonga, California, the average high-temperature is 88.3°F (31.3°C), and the average low-temperature is 63.7°F (17.6°C). The average heat index (a.k.a. 'apparent temperature', 'feels like'), which takes the relative humidity and factors it into the air temperature reading, in September is computed to be 89.2°F (31.8°C).

What is the average humidity in September in Rancho Cucamonga?

In Rancho Cucamonga, California, the average relative humidity in September is 43%.

How many days does it rain in September in Rancho Cucamonga?

In September, the rain falls for 1.8 days. Throughout September, 0.08" (2mm) of precipitation is accumulated.

When it does not snow in Rancho Cucamonga?

In Rancho Cucamonga, snow does not fall in January, March through December.

What is the average length of the day in September in Rancho Cucamonga?

The average day length in September in Rancho Cucamonga, California, is 12h and 22min.

When are sunrise and sunset in September in Rancho Cucamonga?

On the first day of September in Rancho Cucamonga, sunrise is at 6:24 am and sunset at 7:16 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 Rancho Cucamonga have in September?

In Rancho Cucamonga, California, the average sunshine duration in September is 10.7h.

How high is the UV index in September in Rancho Cucamonga?

In Rancho Cucamonga, California, the average daily maximum UV index in September is 6. A UV Index of 6 to 7 symbolizes a high health risk from unsafe exposure to Sun's UV rays.
Average humidity
Average rainfall days
Average snowfall days
Average sunshine days
Average UV index
Average cloud cover
Average visibility

Average temperature in September
Rancho Cucamonga, CA

Average temperature in September - Rancho Cucamonga, CA
  • Average high temperature in September: 88.3°F

The warmest month (with the highest average high temperature) is August (91.8°F).
The month with the lowest average high temperature is December (61.7°F).

  • Average low temperature in September: 63.7°F

The month with the highest average low temperature is August (66.6°F).
The coldest months (with the lowest average low temperature) are February and December (45.3°F).

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Average pressure in September
Rancho Cucamonga, CA

Average pressure in September - Rancho Cucamonga, 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
Rancho Cucamonga, CA

Average wind speed in September - Rancho Cucamonga, CA
  • Average wind speed in September: 4.5mph

The windiest month (with the highest average wind speed) is May (5.9mph).
The calmest month (with the lowest average wind speed) is September (4.5mph).

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Average humidity in September
Rancho Cucamonga, CA

Average humidity in September - Rancho Cucamonga, CA
  • Average humidity in September: 43%

The months with the highest relative humidity are February, March and May (53%).
The month with the lowest relative humidity is August (41%).

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Average rainfall in September
Rancho Cucamonga, CA

Average rainfall in September - Rancho Cucamonga, CA
  • Average rainfall in September: 0.08"

The wettest month (with the highest rainfall) is February (0.98").
The driest month (with the least rainfall) is June (0.04").

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Average rainfall days in September
Rancho Cucamonga, CA

Average rainfall days in September - Rancho Cucamonga, CA
  • Average rainfall days in September: 1.8 days

The month with the highest number of rainy days is March (6.3 days).
The month with the least rainy days is June (0.9 days).

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Average snowfall days in September
Rancho Cucamonga, CA

Average snowfall days in September - Rancho Cucamonga, 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
Rancho Cucamonga, CA

Average daylight in September / Average sunshine in September - Rancho Cucamonga, CA
  • Average daylight in September: 12h and 22min

The month with the longest days is June (Average daylight: 14h and 23min).
The month with the shortest days is December (Average daylight: 9h and 56min).

  • Average sunshine in September: 10h and 42min

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
Rancho Cucamonga, CA

Average sunshine days in September - Rancho Cucamonga, CA
  • Average sunshine days in September: 26 days

The month with the most sunshine days is June (28.3 days).
The month with the least sunshine days is February (22.8 days).

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Average UV index in September
Rancho Cucamonga, CA

Average UV index in September - Rancho Cucamonga, 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
Rancho Cucamonga, CA

Average cloud cover in September - Rancho Cucamonga, CA
  • Average cloud cover in September: 6

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

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Average visibility in September
Rancho Cucamonga, CA

Average visibility in September - Rancho Cucamonga, 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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