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
The introduction of September sees an average high-temperature of a still moderately hot 78.6°F (25.9°C), hardly deviating from August. Despite soaring daytime temperatures, Union City registers a consistent average low-temperature of 56.7°F (13.7°C) in September.Humidity
The months with the lowest humidity are September and October, with an average relative humidity of 62%.Rainfall
Months with rainfall are January through May, September through December. September is the first month it rains in Union City. Throughout September, in the average 1.2 rainfall days, it receives 0.04" (1mm) of precipitation. In Union City, during the entire year, the rain falls for 38 days and collects up to 2.13" (54mm) of precipitation.Daylight
In September, the average length of the day is 12h and 25min.On the first day of September, sunrise is at 6:39 am and sunset at 7:36 pm. On the last day of the month, sunrise is at 7:03 am and sunset at 6:52 pm PDT.
Sunshine
In September, the average sunshine is 11.1h.UV index
In September, the average daily maximum UV index is 5. A UV Index of 3 to 5 symbolizes a moderate health risk from exposure to the Sun's UV radiation for the ordinary person.Note: In September, a daily UV index of 5 turns into the following recommendations:
Undertake protective steps - Preventing sun damage is advised. Solar radiation is at its peak intensity during midday, so it's advisable to stay indoors or in the shade. Loose clothes with a tight weave are optimal for safeguarding yourself against the Sun's rays.
Published by: Weather U.S. | About Us
Data Sources | Weather Forecasting & Climate
Frequently asked questions
What are the temperatures in September?
What is the least humid month?
What is the average humidity in September?
When does it start raining?
How many hours of daylight does Union City have in September?
When is the sunrise / sunset in September?
How many hours of sunshine does Union City have in September?
What is the UV index intensity in September?
Average temperature in September
Union City, CA
- Average high temperature in September: 78.6°F
The warmest months (with the highest average high temperature) are July and August (80.1°F).
The month with the lowest average high temperature is December (56.3°F).
- Average low temperature in September: 56.7°F
The months with the highest average low temperature are August and September (56.7°F).
The coldest month (with the lowest average low temperature) is December (43.7°F).
Average pressure in September
Union City, 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
Union City, CA
- Average wind speed in September: 4.8mph
The windiest month (with the highest average wind speed) is May (6.4mph).
The calmest months (with the lowest average wind speed) are October and November (4.7mph).
Average humidity in September
Union City, CA
- Average humidity in September: 62%
The month with the highest relative humidity is March (73%).
The months with the lowest relative humidity are September and October (62%).
Average rainfall in September
Union City, CA
- Average rainfall in September: 0.04"
The wettest month (with the highest rainfall) is February (0.47").
The driest months (with the least rainfall) are June, July and August (0").
Average rainfall days in September
Union City, CA
- Average rainfall days in September: 1.2 days
The month with the highest number of rainy days is March (7.3 days).
The month with the least rainy days is July (0.3 days).
Average daylight in September /
Average sunshine in September
Union City, CA
- Average daylight in September: 12h and 2min
The month with the longest days is June (Average daylight: 14h and 42min).
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 12min).
The month with the least sunshine is December (Average sunshine: 6h and 0min).
Average sunshine days in September
Union City, CA
- Average sunshine days in September: 28.5 days
The months with the most sunshine days are July and August (30.4 days).
The month with the least sunshine days is February (22.2 days).
Average UV index in September
Union City, 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
Union City, CA
- Average cloud cover in September: 9
The month with the most cloud cover is March (Cloud cover 34).
The month with the least cloud cover is July (Cloud cover 6).
Average visibility in September
Union City, 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).
Union City, California, USA
Weather forecast for your location
2. Allow the app to use your location