September weather forecastFairfax, CA
September
Weather in September
September, the first month of the autumn in Fairfax, is also an agreeable month, with an average temperature ranging between max 70.9°F (21.6°C) and min 56.3°F (13.5°C).Temperature
September temperatures tend to peak at an average high of 70.9°F (21.6°C) and dip to a low of 56.3°F (13.5°C).Humidity
The average relative humidity in September is 73%.Rainfall
In Fairfax, in September, it is raining for 3.4 days, with typically 0.12" (3mm) of accumulated precipitation. Throughout the year, there are 80.3 rainfall days, and 15.98" (406mm) of precipitation is accumulated.Snowfall
January through November are months without snowfall.Daylight
In Fairfax, California, the average length of the day in September is 12h and 25min.On the first day of the month, sunrise is at 6:40 am and sunset at 7:39 pm. On the last day of September, sunrise is at 7:05 am and sunset at 6:54 pm PDT.
Sunshine
In September, the average sunshine is 10.5h.UV index
June through September, with an average maximum UV index of 5, are months with the highest UV index. A UV Index of 3 to 5 symbolizes a medium health hazard from exposure to the Sun's UV rays for the ordinary person.Note: In September, a daily UV index of 5 turns into the following recommendations:
Exercise prevention - Precautions against solar damage are endorsed. Avoid the Sun's strongest UV rays by seeking shade and limiting exposure during midday. For a sun-safe wardrobe, go for clothes that are tightly woven and generously sized.
Published by: Weather U.S. | About Us
Data Sources | Weather Forecasting & Climate
Frequently asked questions
Average temperature in September
Fairfax, CA
- Average high temperature in September: 70.9°F
The warmest month (with the highest average high temperature) is September (70.9°F).
The month with the lowest average high temperature is December (55.2°F).
- Average low temperature in September: 56.3°F
The month with the highest average low temperature is September (56.3°F).
The coldest month (with the lowest average low temperature) is December (46°F).
Average pressure in September
Fairfax, CA
- Average pressure in September: 29.92"Hg
The month with the highest atmospheric pressure is January (30.13"Hg).
The months with the lowest atmospheric pressure are June, August and September (29.92"Hg).
Average wind speed in September
Fairfax, CA
- Average wind speed in September: 6.3mph
The windiest months (with the highest average wind speed) are April and May (8.3mph).
The calmest month (with the lowest average wind speed) is November (5.9mph).
Average humidity in September
Fairfax, CA
- Average humidity in September: 73%
The month with the highest relative humidity is August (78%).
The month with the lowest relative humidity is October (69%).
Average rainfall in September
Fairfax, CA
- Average rainfall in September: 0.12"
The wettest month (with the highest rainfall) is February (3.43").
The driest months (with the least rainfall) are July and August (0.08").
Average rainfall days in September
Fairfax, CA
- Average rainfall days in September: 3.4 days
The month with the highest number of rainy days is March (12.8 days).
The month with the least rainy days is July (2.3 days).
Average snowfall days in September
Fairfax, CA
- Average snowfall days in September: 0 days
The month with the highest number of snowfall days is December (0.1 days).
The months with the least snowfall days are January, February, March, April, May, June, July, August, September, October and November (0 days).
Average daylight in September /
Average sunshine in September
Fairfax, CA
- Average daylight in September: 12h and 24min
The month with the longest days is June (Average daylight: 14h and 48min).
The month with the shortest days is December (Average daylight: 9h and 36min).
- Average sunshine in September: 10h and 30min
The month with the most sunshine is July (Average sunshine: 11h and 12min).
The month with the least sunshine is December (Average sunshine: 5h and 36min).
Average sunshine days in September
Fairfax, CA
- Average sunshine days in September: 24.1 days
The months with the most sunshine days are June and July (24.8 days).
The month with the least sunshine days is March (16.6 days).
Average UV index in September
Fairfax, CA
- Average UV index in September: 5
The months with the highest UV index are June, July, August and September (UV index 5).
The months with the lowest UV index are February, November and December (UV index 3).
Average cloud cover in September
Fairfax, CA
- Average cloud cover in September: 19
The month with the most cloud cover is March (Cloud cover 39).
The month with the least cloud cover is September (Cloud cover 19).
Average visibility in September
Fairfax, 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).
