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
In Vallejo, the warmest period comes during July and September, when the average high-temperature touches 80.1°F (26.7°C).Humidity
The months with the lowest humidity in Vallejo are September and October, with an average relative humidity of 60%.Rainfall
In Vallejo, in September, it is raining for 2.1 days, with typically 0.08" (2mm) of accumulated precipitation. In Vallejo, during the entire year, the rain falls for 56.9 days and collects up to 4.88" (124mm) of precipitation.Daylight
In September, the average length of the day is 12h and 25min.On the first day of the month, sunrise is at 6:39 am and sunset at 7:38 pm. On the last day of September, sunrise is at 7:04 am and sunset at 6:52 pm PDT.
Sunshine
In Vallejo, the average sunshine in September is 11.1h.UV index
The average daily maximum UV index in September is 5. A UV Index of 3 to 5 symbolizes a moderate health risk from exposure to the Sun's UV rays for average individuals.Note: In September, the average maximum UV index of 5 translates into the following recommendations:
Adopt protective measures - Requirement to safeguard skin and eyes from harm exists. The best time to avoid the Sun's harmful UV radiation is during midday when it's most potent. Arm yourself against UV rays' harm with protective apparel and UV-filtering shades.
Published by: Weather U.S. | About Us
Data Sources | Weather Forecasting & Climate
Frequently asked questions
What month is the hottest?
What are September temperatures?
What are the least humid months?
What is the average humidity in September?
How much does it rain in September?
What is the average length of the day in September in Vallejo?
When is the sunrise / sunset in September?
How many hours of sunshine does Vallejo have in September?
What is the UV index reading in September?
Average temperature in September
Vallejo, CA
- Average high temperature in September: 80.1°F
The warmest months (with the highest average high temperature) are July and September (80.1°F).
The month with the lowest average high temperature is December (55.4°F).
- Average low temperature in September: 56.3°F
The month with the highest average low temperature is August (56.5°F).
The coldest month (with the lowest average low temperature) is January (43°F).
Average pressure in September
Vallejo, CA
- Average pressure in September: 29.92"Hg
The month with the highest atmospheric pressure is January (30.14"Hg).
The month with the lowest atmospheric pressure is June (29.91"Hg).
Average wind speed in September
Vallejo, CA
- Average wind speed in September: 5.5mph
The windiest month (with the highest average wind speed) is May (7.1mph).
The calmest month (with the lowest average wind speed) is November (4.6mph).
Average humidity in September
Vallejo, CA
- Average humidity in September: 60%
The month with the highest relative humidity is March (75%).
The months with the lowest relative humidity are September and October (60%).
Average rainfall in September
Vallejo, CA
- Average rainfall in September: 0.08"
The wettest month (with the highest rainfall) is February (1.14").
The driest months (with the least rainfall) are July and August (0.04").
Average rainfall days in September
Vallejo, CA
- Average rainfall days in September: 2.1 days
The month with the highest number of rainy days is March (10.2 days).
The month with the least rainy days is August (0.9 days).
Average daylight in September /
Average sunshine in September
Vallejo, 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 1min
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 42min).
Average sunshine days in September
Vallejo, CA
- Average sunshine days in September: 26 days
The month with the most sunshine days is July (27.2 days).
The month with the least sunshine days is March (18.8 days).
Average UV index in September
Vallejo, CA
- Average UV index in September: 5
The month with the highest UV index is June (UV index 6).
The months with the lowest UV index are January, February, November and December (UV index 3).
Average cloud cover in September
Vallejo, CA
- Average cloud cover in September: 11
The month with the most cloud cover is March (Cloud cover 37).
The month with the least cloud cover is July (Cloud cover 9).
Average visibility in September
Vallejo, 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).
Vallejo, California, USA
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