September weather forecast
Sierra City, CA

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Weather in September

The first month of the autumn, September, is also a moderately hot month in Sierra City, California, with temperature in the range of an average high of 73.8°F (23.2°C) and an average low of 42.3°F (5.7°C).

Temperature

Start of September brings a slight shift in the average high-temperature, dipping a bit from August's warm 81.1°F (27.3°C) to a still moderately hot 73.8°F (23.2°C). Sierra City's average nighttime temperature descends significantly from the day's peak in September, settling at a cold 42.3°F (5.7°C).

Humidity

The average relative humidity in September is 46%.

Rainfall

In Sierra City, during September, the rain falls for 4.5 days and regularly aggregates up to 0.43" (11mm) of precipitation. Throughout the year, there are 80.1 rainfall days, and 22.95" (583mm) of precipitation is accumulated.

Snowfall

Months with snowfall are January through June, September through December. September is the first month it typically snows. Throughout September, in the average 0.4 snowfall days, it receives 1.02" (26mm) of snow. In Sierra City, during the entire year, snow falls for 69.3 days and aggregates up to 103.5" (2629mm) of snow.

Daylight

In September, the average length of the day is 12h and 26min.
On the first day of the month, sunrise is at 6:31 am and sunset at 7:32 pm. On the last day of September, sunrise is at 6:58 am and sunset at 6:45 pm PDT.

Sunshine

In Sierra City, the average sunshine in September is 11h.

UV index

In Sierra City, the average daily maximum UV index in September is 3. A UV Index reading of 3 to 5 represents a moderate health risk from unprotected exposure to Sun's UV rays for ordinary individuals.
Note: The maximum UV index of 3 during September leads to these instructions:
Guard yourself - An obligation to protect skin and eyes from harm exists. Sun exposure should be minimized, especially during midday, to avoid harmful UV radiation. Combat UV radiation's detrimental effects with sun-safe clothing and UV-blocking eyewear. Attention! Nearly twice the Sun's UV radiation can be reflected by snow.
Updated: Aug 18, 2024
Published by: Weather U.S. | About Us
Data Sources | Weather Forecasting & Climate

Frequently asked questions

What is the average September temperature?

In Sierra City, in September, the average high-temperature is 73.8°F (23.2°C), and the average low-temperature is 42.3°F (5.7°C). The average heat index (a.k.a. 'apparent temperature', 'real feel'), which represents the influence of relative humidity on air temperature, in August is computed to be 80.6°F (27°C).

What is the average humidity in September?

In Sierra City, the average relative humidity in September is 46%.

How many days does it rain in September?

In September, the rain falls for 4.5 days. Throughout September, 0.43" (11mm) of precipitation is accumulated.

When does it start snowing?

September is the first month it typically snows. Throughout September, in the average 0.4 snowfall days, it receives 1.02" (26mm) of snow.

How many hours of daylight does Sierra City have in September?

In Sierra City, the average day length in September is 12h and 26min.

When are sunrise and sunset in September in Sierra City?

On the first day of September, sunrise is at 6:31 am and sunset at 7:32 pm. On the last day of the month, sunrise is at 6:58 am and sunset at 6:45 pm PDT.

How long on average sun shines in September in Sierra City?

In September, the average sunshine duration in Sierra City is 11h.

What is the UV index reading in September?

The average daily maximum UV index in September is 3. A UV Index of 3 to 5 symbolizes a moderate vulnerability from exposure to Sun's UV rays.
Average humidity
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
Sierra City, CA

Average temperature in September - Sierra City, CA
  • Average high temperature in September: 73.8°F

The warmest month (with the highest average high temperature) is July (82.9°F).
The month with the lowest average high temperature is December (37.2°F).

  • Average low temperature in September: 42.3°F

The month with the highest average low temperature is July (47.5°F).
The coldest month (with the lowest average low temperature) is December (21.6°F).

Average pressure in September
Sierra City, CA

Average pressure in September - Sierra City, CA
  • Average pressure in September: 29.93"Hg

The month with the highest atmospheric pressure is January (30.19"Hg).
The month with the lowest atmospheric pressure is June (29.9"Hg).

Average wind speed in September
Sierra City, CA

Average wind speed in September - Sierra City, CA
  • Average wind speed in September: 5.2mph

The windiest month (with the highest average wind speed) is March (6.6mph).
The calmest months (with the lowest average wind speed) are August and September (5.2mph).

Average humidity in September
Sierra City, CA

Average humidity in September - Sierra City, CA
  • Average humidity in September: 46%

The months with the highest relative humidity are January and March (81%).
The months with the lowest relative humidity are July and August (40%).

Average rainfall in September
Sierra City, CA

Average rainfall in September - Sierra City, CA
  • Average rainfall in September: 0.43"

The wettest month (with the highest rainfall) is March (4.02").
The driest month (with the least rainfall) is August (0.2").

Average rainfall days in September
Sierra City, CA

Average rainfall days in September - Sierra City, CA
  • Average rainfall days in September: 4.5 days

The month with the highest number of rainy days is May (11.8 days).
The month with the least rainy days is July (3.3 days).

Average snowfall in September
Sierra City, CA

Average snowfall in September - Sierra City, CA
  • Average snowfall in September: 1.02"

The month with the highest snowfall is December (22.52").
The months with the least snowfall are July and August (0").

Average snowfall days in September
Sierra City, CA

Average snowfall days in September - Sierra City, CA
  • Average snowfall days in September: 0.4 days

The month with the highest number of snowfall days is March (14.7 days).
The months with the least snowfall days are July and August (0 days).

Average daylight in September /
Average sunshine in September
Sierra City, CA

Average daylight in September / Average sunshine in September - Sierra City, 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

The month with the most sunshine is July (Average sunshine: 12h).
The month with the least sunshine is January (Average sunshine: 5h).

Average sunshine days in September
Sierra City, CA

Average sunshine days in September - Sierra City, CA
  • Average sunshine days in September: 25 days

The month with the most sunshine days is August (26 days).
The month with the least sunshine days is March (11.8 days).

Average UV index in September
Sierra City, CA

Average UV index in September - Sierra City, CA
  • Average UV index in September: 3

The months with the highest UV index are June, July and August (UV index 5).
The month with the lowest UV index is November (UV index 1).

Average cloud cover in September
Sierra City, CA

Average cloud cover in September - Sierra City, CA
  • Average cloud cover in September: 12

The month with the most cloud cover is March (Cloud cover 47).
The month with the least cloud cover is July (Cloud cover 7).

Average visibility in September
Sierra City, CA

Average visibility in September - Sierra City, CA
  • Average visibility in September: 6mi

The months with the highest visibility are May, June, July, August, September, October and November (6mi).
The months with the lowest visibility are January and December (4mi).

Sierra City, California, USA

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