September weather forecast
Stonyford, CA

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Weather in September

September, the first month of the autumn in Stonyford, is still a tropical month, with an average temperature ranging between min 59.9°F (15.5°C) and max 87.4°F (30.8°C).

Temperature

Stonyford experiences a moderate temperature shift at the start of September, with average high-temperatures adjusting a bit from a tropical 93.9°F (34.4°C) in August to a still hot 87.4°F (30.8°C). September nights experience a distinct temperature drop from the daily highs, with an average low-temperature of 59.9°F (15.5°C).

Humidity

The months with the lowest humidity in Stonyford are July through September, with an average relative humidity of 35%.

Rainfall

In Stonyford, in September, during 2.2 rainfall days, 0.12" (3mm) of precipitation is typically accumulated. Throughout the year, in Stonyford, there are 71.4 rainfall days, and 14.02" (356mm) of precipitation is accumulated.

Daylight

The average length of the day in September is 12h and 26min.
On the first day of September in Stonyford, sunrise is at 6:39 am and sunset at 7:40 pm. On the last day of the month, sunrise is at 7:06 am and sunset at 6:53 pm PDT.

Sunshine

In Stonyford, the average sunshine in September is 11.2h.

UV index

In September, the average daily maximum UV index in Stonyford is 5. A UV Index estimate of 3 to 5 represents a moderate threat to health from unprotected exposure to Sun's UV rays for average individuals.
Note: The average daily UV index of 5 in September transforms into the following instructions:
Ensure safety - Sun damage prevention is strongly urged. Avoiding the Sun during its peak radiation time around midday is a healthy practice. Tightly woven clothing, when worn loosely, shields effectively against the Sun.
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Frequently asked questions

How hot is it in Stonyford in September?

The high-temperature, in September, in Stonyford, records 87.4°F (30.8°C), while the low-temperature is 59.9°F (15.5°C). The average heat index (a.k.a. 'apparent temperature', 'felt air temperature'), which combines air temperature and relative humidity, in June is evaluated at 87.8°F (31°C).

What is the least humid month in Stonyford?

The months with the lowest humidity are July through September, with an average relative humidity of 35%.

What is the average humidity in September in Stonyford?

In Stonyford, the average relative humidity in September is 35%.

How much does it rain in Stonyford in September?

In Stonyford, California, in September, it is raining for 2.2 days, with typically 0.12" (3mm) of accumulated precipitation.

How many hours of daylight does Stonyford have in September?

In Stonyford, California, the average day length in September is 12h and 26min.

When is the sunrise / sunset in September in Stonyford?

In September, on the first day of the month, sunrise is at 6:39 am and sunset at 7:40 pm. On the last day of the month, in Stonyford, California, sunrise is at 7:06 am and sunset at 6:53 pm PDT.

How many hours of sunshine does Stonyford have in September?

The average sunshine duration in September in Stonyford is 11.2h.

What is the UV index reading in September in Stonyford?

In September, the average daily maximum UV index in Stonyford, California, is 5. A UV Index reading of 3 to 5 represents a moderate vulnerability from exposure to the Sun's UV radiation.
Average humidity
Average rainfall days
Average daylight
Average sunshine
Average sunshine days
Average UV index
Average cloud cover
Average visibility

Average temperature in September
Stonyford, CA

Average temperature in September - Stonyford, CA
  • Average high temperature in September: 87.4°F

The warmest month (with the highest average high temperature) is July (95.4°F).
The month with the lowest average high temperature is December (52.7°F).

  • Average low temperature in September: 59.9°F

The month with the highest average low temperature is July (63.1°F).
The coldest month (with the lowest average low temperature) is December (39.4°F).

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Average pressure in September
Stonyford, CA

Average pressure in September - Stonyford, CA
  • Average pressure in September: 29.92"Hg

The month with the highest atmospheric pressure is January (30.15"Hg).
The months with the lowest atmospheric pressure are June, July and August (29.91"Hg).

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Average wind speed in September
Stonyford, CA

Average wind speed in September - Stonyford, CA
  • Average wind speed in September: 5.5mph

The windiest month (with the highest average wind speed) is March (6.1mph).
The calmest month (with the lowest average wind speed) is August (4.9mph).

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Average humidity in September
Stonyford, CA

Average humidity in September - Stonyford, CA
  • Average humidity in September: 35%

The month with the highest relative humidity is March (69%).
The months with the lowest relative humidity are July, August and September (35%).

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Average rainfall in September
Stonyford, CA

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

The wettest month (with the highest rainfall) is February (2.68").
The driest month (with the least rainfall) is July (0.04").

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Average rainfall days in September
Stonyford, CA

Average rainfall days in September - Stonyford, CA
  • Average rainfall days in September: 2.2 days

The month with the highest number of rainy days is March (12.5 days).
The month with the least rainy days is July (1 days).

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

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

The month with the longest days is June (Average daylight: 14h and 54min).
The month with the shortest days is December (Average daylight: 9h and 24min).

  • Average sunshine in September: 11h and 1min

The month with the most sunshine is July (Average sunshine: 12h and 6min).
The month with the least sunshine is December (Average sunshine: 5h and 48min).

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Average sunshine days in September
Stonyford, CA

Average sunshine days in September - Stonyford, CA
  • Average sunshine days in September: 27.3 days

The month with the most sunshine days is July (29.8 days).
The month with the least sunshine days is March (17 days).

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Average UV index in September
Stonyford, CA

Average UV index in September - Stonyford, CA
  • Average UV index in September: 5

The months with the highest UV index are June and July (UV index 7).
The months with the lowest UV index are January, February, November and December (UV index 3).

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Average cloud cover in September
Stonyford, CA

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

The month with the most cloud cover is March (Cloud cover 37).
The month with the least cloud cover is July (Cloud cover 4).

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Average visibility in September
Stonyford, CA

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

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