September weather forecast and climate
Fontana, CA

Weather in September

September, the first month of the autumn, in Fontana, is also a hot month, with temperature in the range of an average low of 63.9°F (17.7°C) and an average high of 88.3°F (31.3°C).

Temperature

In Fontana, the average high-temperature is practically the same as in August - a still tropical 88.3°F (31.3°C). In September, in Fontana, the average low-temperature is 63.9°F (17.7°C).

Heat index

The average heat index is appraised at a tropical 88.9°F (31.6°C). Constant exposure and activity lead to possible fatigue. Prolonged exercise 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 'felt air temperature', 'real feel', 'apparent temperature', or 'feels like', is a measure of how hot it feels when the actual air humidity is factored in. Additional factors like metabolic differences, pregnancy, clothing, and activity influence one's weather impression. 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 particularly important for children. 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

The average relative humidity in September is 42%.

Rainfall

In Fontana, during September, the rain falls for 2.4 days and regularly aggregates up to 0.12" (3mm) of precipitation. Throughout the year, in Fontana, California, there are 48.1 rainfall days, and 6.89" (175mm) of precipitation is accumulated.

Snowfall

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

Daylight

The average length of the day is 12.4h.

Sunshine

The average sunshine in Fontana is 10.7h.

UV index

The average daily maximum UV index in September is 6. A UV Index of 6 to 7 symbolizes a high health hazard from unsafe exposure to the UV radiation for ordinary individuals.
Note: The daily maximum UV index of 6 in September interpret into the following advice:
Take precautions and utilize sun safety practices. Protection against the skin and eye damage is required. Seek shade and minimize exposure to direct Sun in a period between 10 a.m. and 4 p.m. when UV radiation is most intense; keep in mind that shade structures like parasols or canopies do not provide perfect sun protection. Sun-protective clothing, a long-sleeved shirt and pants, a wide-brimmed hat, and UVA and UVB-blocking sunglasses are particularly helpful in blocking UV radiation's harmful effects.
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FAQ

What is the temperature in September in Fontana?

In September, in Fontana, California, the average high-temperature is 88.3°F (31.3°C), and the average low-temperature is 63.9°F (17.7°C). In September, the average heat index (a.k.a. 'feels like', 'felt air temperature'), that calculates temperature value influenced by the moisture in the air, is appraised at 88.9°F (31.6°C).

What is the average humidity in September in Fontana?

In September, the average relative humidity in Fontana, California, is 42%.

How much does it rain in Fontana in September?

In Fontana, California, in September, during 2.4 rainfall days, 0.12" (3mm) of precipitation is typically accumulated.

When it does not snow in Fontana?

January, March through December are months without snowfall in Fontana, California.

How many hours of daylight does Fontana have in September?

In September, the average length of the day in Fontana is 12.4h.

How many hours of sunshine does Fontana have in September?

In September, the average sunshine in Fontana, California, is 10.7h.

How high is the UV index in September in Fontana?

In Fontana, California, the average daily maximum UV index in September is 6. A UV Index of 6 to 7 symbolizes a high health threat from the exposure to the Sun's UV rays.

Average temperature in September
Fontana, CA

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

The warmest month (with the highest average high temperature) is August (92.1°F).
The month with the lowest average high temperature is December (60.8°F).

  • Average low temperature in September: 63.9°F

The month with the highest average low temperature is August (67.3°F).
The coldest months (with the lowest average low temperature) are February and December (44.2°F).

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Average pressure in September
Fontana, CA

Average pressure in September - Fontana, CA
  • Average pressure in September: 29.87"

The month with the highest atmospheric pressure is January (30.1").
The month with the lowest atmospheric pressure is June (29.85").

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Average wind speed in September
Fontana, CA

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

The windiest months (with the highest average wind speed) are April and May (6mph).
The calmest month (with the lowest average wind speed) is September (4.5mph).

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Average humidity in September
Fontana, CA

Average humidity in September - Fontana, CA
  • Average humidity in September: 42%

Months with the highest relative humidity are February, March and May (52%).
The month with the lowest relative humidity is August (39%).

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Average rainfall in September
Fontana, CA

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

The wettest month (with the highest rainfall) is February (1.57").
The driest month (with the least rainfall) is June (0.04").

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Average rainfall days in September
Fontana, CA

Average rainfall days in September - Fontana, CA
  • Average rainfall days in September: 2.4 days

The month with the highest number of rainy days is March (7.5 days).
The month with the least rainy days is June (1.2 days).

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Average snowfall days in September
Fontana, CA

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

The month with the highest number of snowfall days is February (0.1 days).
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
Fontana, CA

Average daylight in September / Average sunshine in September - Fontana, 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: 10.7h

Months with the most sunshine are June, July and August (Average sunshine: 12.1h).
The month with the least sunshine is December (Average sunshine: 6.9h).

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Average sunshine days in September
Fontana, CA

Average sunshine days in September - Fontana, CA
  • Average sunshine days in September: 25.9 days

The month with the most sunshine days is June (28.3 days).
The month with the least sunshine days is February (21.1 days).

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Average UV index in September
Fontana, CA

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

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
Fontana, CA

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

Months with the most cloud cover are February, March and December (Cloud cover 21).
The month with the least cloud cover is August (Cloud cover 4).

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Average visibility in September
Fontana, CA

Average visibility in September - Fontana, 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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