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 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 begins with an average high-temperature of a still warm 81.1°F (27.3°C), reflecting close similarity to the preceding month. September nights in Sonoma indicate a noticeable temperature drop from the daytime highs, with an average reading lowering to a fresh 54.7°F (12.6°C).Heat index
The heat index value for September is appraised at 82.4°F (28°C). Continued exposure and engagement in activity might trigger tiredness and subsequently heat cramps.Records show heat index calculations are tailored for shaded regions and mild winds. Direct sunlight can potentially boost the heat index by 15 Fahrenheit (8 Celsius) degrees.
Note: The heat index, also known as 'real feel' or 'apparent temperature', combines air temperature and relative humidity to represent a human perceived temperature equivalent. The effect is personal, with varied weather perceptions among individuals due to differences in body mass, stature, and physical activity. Consider the fact that direct sun exposure can influence how hot one feels, potentially raising the heat index by 15 Fahrenheit (8 Celsius) degrees. Heat index values are especially crucial for babies and toddlers. Youngsters often neglect the necessity for rest and hydration. Thirst is a sign of advancing dehydration - thus the importance of maintaining hydration, specifically during long-lasting physical activities.
Humidity
With an average relative humidity of 59%, September is the least humid month.Rainfall
In Sonoma, California, in September, it is raining for 2.4 days, with typically 0.08" (2mm) of accumulated precipitation. In Sonoma, during the entire year, the rain falls for 73.3 days and collects up to 15.47" (393mm) of precipitation.Daylight
In Sonoma, the average length of the day in September is 12h and 25min.On the first day of September, sunrise is at 6:40 am and sunset at 7:39 pm. On the last day of the month, sunrise is at 7:05 am and sunset at 6:53 pm PDT.
Sunshine
In September, the average sunshine is 11h.UV index
In Sonoma, the average daily maximum UV index in September is 5. A UV Index estimate of 3 to 5 represents a medium vulnerability from unprotected exposure to Sun's UV rays for ordinary individuals.Note: The daily high UV index of 5 during September translates into the following recommendations:
Guard yourself - An obligation to protect skin and eyes from harm exists. Protect yourself from the midday Sun's peak UV radiation by minimizing exposure. Limit sun-induced ocular harm with sunglasses that feature UVA and UVB filtration.
Published by: Weather U.S. | About Us
Data Sources | Weather Forecasting & Climate
Frequently asked questions
What is the usual temperature for Sonoma in September?
What is the least humid month?
What is the average humidity in September?
How much does it rain in September?
How many hours of daylight does Sonoma have in September?
When are sunrise and sunset in September?
How long on average sun shines in September?
What is the UV index reading in September?
Average temperature in September
Sonoma, CA
- Average high temperature in September: 81.1°F
The warmest month (with the highest average high temperature) is August (82.9°F).
The month with the lowest average high temperature is December (55°F).
- Average low temperature in September: 54.7°F
The month with the highest average low temperature is August (54.9°F).
The coldest month (with the lowest average low temperature) is December (41.4°F).
Average pressure in September
Sonoma, CA
- Average pressure in September: 29.92"Hg
The month with the highest atmospheric pressure is January (30.13"Hg).
The month with the lowest atmospheric pressure is June (29.91"Hg).
Average wind speed in September
Sonoma, CA
- Average wind speed in September: 4.8mph
The windiest month (with the highest average wind speed) is May (6.2mph).
The calmest month (with the lowest average wind speed) is November (4.4mph).
Average humidity in September
Sonoma, CA
- Average humidity in September: 59%
The month with the highest relative humidity is March (76%).
The month with the lowest relative humidity is September (59%).
Average rainfall in September
Sonoma, CA
- Average rainfall in September: 0.08"
The wettest month (with the highest rainfall) is February (3.43").
The driest months (with the least rainfall) are July and August (0.04").
Average rainfall days in September
Sonoma, CA
- Average rainfall days in September: 2.4 days
The month with the highest number of rainy days is March (13.4 days).
The month with the least rainy days is August (0.8 days).
Average daylight in September /
Average sunshine in September
Sonoma, CA
- Average daylight in September: 12h and 2min
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: 11h and 0min
The month with the most sunshine is July (Average sunshine: 12h and 0min).
The month with the least sunshine is December (Average sunshine: 5h and 36min).
Average sunshine days in September
Sonoma, CA
- Average sunshine days in September: 26.7 days
The month with the most sunshine days is July (28.7 days).
The month with the least sunshine days is March (16.1 days).
Average UV index in September
Sonoma, CA
- Average UV index in September: 5
The months with the highest UV index are June and July (UV index 6).
The months with the lowest UV index are January, February, November and December (UV index 3).
Average cloud cover in September
Sonoma, CA
- Average cloud cover in September: 10
The month with the most cloud cover is March (Cloud cover 40).
The month with the least cloud cover is July (Cloud cover 8).
Average visibility in September
Sonoma, 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).
Sonoma, California, USA
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