Contents
- Weather in September
- Frequently asked questions
- Average temperature in September
- Average pressure in September
- Average wind speed in September
- Average humidity in September
- Average rainfall in September
- Average rainfall days in September
- Average snowfall in September
- Average snowfall days in September
- Average daylight in September
- Average sunshine in September
- Average sunshine days in September
- Average UV index in September
- Average cloud cover in September
- Average visibility in September
Weather in September
Temperature
September heralds a minor drop in average high-temperature, sliding from August's tropical 89.2°F (31.8°C) to a warm 83.8°F (28.8°C). Alta Sierra experiences a substantial decline from the daytime high temperatures in September, settling on an average low of 56.5°F (13.6°C).Heat index
During September, the heat index is evaluated at 82.4°F (28°C). Long-standing exposure coupled with ongoing activity could result in exhaustion, possibly causing heat cramps.Heat index values are typically calculated for conditions of shade and a light breeze. If directly exposed to the sun, the heat index could rise by 15 Fahrenheit (8 Celsius) degrees.
Note: The heat index, also known as 'real feel' or 'apparent temperature', is an index that combines air temperature and relative humidity to determine the human-perceived temperature equivalent. The effect of weather is individual, with a variety of people experiencing it differently due to distinctions in body mass, height, and level of activity. Understand that direct sun rays can influence the weather's impact, leading to an increase in the heat index by 15 Fahrenheit (8 Celsius) degrees. Heat index values are particularly important for children. Youngsters are usually more at risk than adults, considering they sweat less. Additionally, their high skin surface area compared to their little bodies and their high heat production due to activity increases their risk.
Humidity
In September, the average relative humidity is 40%.Rainfall
In Alta Sierra, during September, the rain falls for 2.3 days and regularly aggregates up to 0.28" (7mm) of precipitation. In Alta Sierra, during the entire year, the rain falls for 82 days and collects up to 33.11" (841mm) of precipitation.Snowfall
In Alta Sierra, snow does not fall in June through October.Daylight
In September, the average length of the day in Alta Sierra is 12h and 26min.On the first day of September in Alta Sierra, sunrise is at 6:33 am and sunset at 7:34 pm. On the last day of the month, sunrise is at 7:00 am and sunset at 6:47 pm PDT.
Sunshine
The average sunshine in September is 11.2h.UV index
In September, the average daily maximum UV index is 5. A UV Index estimate of 3 to 5 represents a medium vulnerability from exposure to the Sun's UV rays for ordinary individuals.Note: In September, the UV index of 5 transforms into the following advice:
Prioritize safety - The need to safeguard skin and eyes from harm is emphasized. Sun exposure should be minimized, especially during midday, to avoid harmful UV radiation. Opt for tightly woven and loose clothing to enhance protection from the Sun.
Published by: Weather U.S. | About Us
Data Sources | Weather Forecasting & Climate
Frequently asked questions
How hot is it in September?
What is the average humidity in September?
How many days does it rain in September?
When it does not snow?
How many hours of daylight does Alta Sierra have in September?
When is the sunrise / sunset in September?
How long on average sun shines in September?
What is the UV index intensity in September in Alta Sierra?
Average temperature in September
Alta Sierra, CA
- Average high temperature in September: 83.8°F
The warmest month (with the highest average high temperature) is July (90.1°F).
The month with the lowest average high temperature is December (51.3°F).
- Average low temperature in September: 56.5°F
The month with the highest average low temperature is July (60.1°F).
The coldest month (with the lowest average low temperature) is December (37.2°F).
Average pressure in September
Alta Sierra, CA
- Average pressure in September: 29.92"Hg
The month with the highest atmospheric pressure is January (30.17"Hg).
The month with the lowest atmospheric pressure is June (29.9"Hg).
Average wind speed in September
Alta Sierra, CA
- Average wind speed in September: 5.2mph
The windiest month (with the highest average wind speed) is February (6mph).
The calmest month (with the lowest average wind speed) is August (4.8mph).
Average humidity in September
Alta Sierra, CA
- Average humidity in September: 40%
The month with the highest relative humidity is March (75%).
The month with the lowest relative humidity is July (37%).
Average rainfall in September
Alta Sierra, CA
- Average rainfall in September: 0.28"
The wettest month (with the highest rainfall) is March (6.57").
The driest months (with the least rainfall) are July and August (0.04").
Average rainfall days in September
Alta Sierra, CA
- Average rainfall days in September: 2.3 days
The month with the highest number of rainy days is March (15.1 days).
The month with the least rainy days is July (1.1 days).
Average snowfall in September
Alta Sierra, CA
- Average snowfall in September: 0"
The month with the highest snowfall is February (6.42").
The months with the least snowfall are June, July, August, September and October (0").
Average snowfall days in September
Alta Sierra, CA
- Average snowfall days in September: 0 days
The month with the highest number of snowfall days is March (2.4 days).
The months with the least snowfall days are June, July, August, September and October (0 days).
Average daylight in September /
Average sunshine in September
Alta Sierra, 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 30min).
- Average sunshine in September: 11h and 1min
The month with the most sunshine is July (Average sunshine: 12h and 12min).
The month with the least sunshine is January (Average sunshine: 5h and 42min).
Average sunshine days in September
Alta Sierra, CA
- Average sunshine days in September: 26.9 days
The month with the most sunshine days is July (29.8 days).
The month with the least sunshine days is March (14.8 days).
Average UV index in September
Alta Sierra, CA
- Average UV index in September: 5
The month with the highest UV index is July (UV index 7).
The month with the lowest UV index is November (UV index 2).
Average cloud cover in September
Alta Sierra, CA
- Average cloud cover in September: 8
The month with the most cloud cover is March (Cloud cover 41).
The month with the least cloud cover is July (Cloud cover 4).
Average visibility in September
Alta Sierra, 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).
Alta Sierra, California, USA
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