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
The arrival of September corresponds with a minor reduction in the average high-temperature, down from August's moderately hot 85.5°F (29.7°C) to a still warm 78.1°F (25.6°C). Swansea reports a consistent average low-temperature of 60.3°F (15.7°C) throughout September nights.Humidity
In Swansea, the average relative humidity in September is 22%.Rainfall
The months with the least rainfall are June and September Rain falls for 2.3 days and accumulates 0.16" (4mm) of rain.Snowfall
May through October are months without snowfall.Daylight
In Swansea, the average length of the day in September is 12h and 24min.On the first day of the month, sunrise is at 6:23 am and sunset at 7:19 pm. On the last day of September, sunrise is at 6:46 am and sunset at 6:35 pm PDT.
Sunshine
The average sunshine in September is 10.9h.UV index
In September, the average daily maximum UV index is 5. A UV Index value of 3 to 5 symbolizes a moderate health risk from unprotected exposure to Sun's UV rays for the average person.Note: In September, the UV index of 5 transforms into the following advice:
Guard yourself - An obligation to protect skin and eyes from harm exists. Limiting exposure to the direct Sun during midday hours can help prevent harmful UV radiation effects. In the presence of strong sunlight, it's crucial to wear sunglasses that ward off UVA and UVB 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 average humidity in September?
What is the driest month?
How much does it rain in September?
When it does not snow?
What is the average length of the day in September?
When are sunrise and sunset in September in Swansea?
How many hours of sunshine does Swansea have in September?
What is the UV index reading in September?
Average temperature in September
Swansea, CA
- Average high temperature in September: 78.1°F
The warmest month (with the highest average high temperature) is July (86°F).
The month with the lowest average high temperature is December (46.9°F).
- Average low temperature in September: 60.3°F
The month with the highest average low temperature is July (69.1°F).
The coldest month (with the lowest average low temperature) is December (31.5°F).
Average pressure in September
Swansea, CA
- Average pressure in September: 29.89"Hg
The month with the highest atmospheric pressure is January (30.14"Hg).
The month with the lowest atmospheric pressure is June (29.83"Hg).
Average wind speed in September
Swansea, CA
- Average wind speed in September: 6.2mph
The windiest months (with the highest average wind speed) are April, May and June (7.6mph).
The calmest month (with the lowest average wind speed) is November (5.8mph).
Average humidity in September
Swansea, CA
- Average humidity in September: 22%
The month with the highest relative humidity is December (47%).
The month with the lowest relative humidity is August (19%).
Average rainfall in September
Swansea, CA
- Average rainfall in September: 0.16"
The wettest month (with the highest rainfall) is December (0.67").
The driest months (with the least rainfall) are June and September (0.16").
Average rainfall days in September
Swansea, CA
- Average rainfall days in September: 2.3 days
The month with the highest number of rainy days is March (5.7 days).
The month with the least rainy days is September (2.3 days).
Average snowfall in September
Swansea, CA
- Average snowfall in September: 0"
The month with the highest snowfall is December (1.18").
The months with the least snowfall are May, June, July, August, September and October (0").
Average snowfall days in September
Swansea, CA
- Average snowfall days in September: 0 days
The month with the highest number of snowfall days is December (1.2 days).
The months with the least snowfall days are May, June, July, August, September and October (0 days).
Average daylight in September /
Average sunshine in September
Swansea, CA
- Average daylight in September: 12h and 2min
The month with the longest days is June (Average daylight: 14h and 36min).
The month with the shortest days is December (Average daylight: 9h and 42min).
- Average sunshine in September: 10h and 5min
The month with the most sunshine is June (Average sunshine: 12h and 12min).
The months with the least sunshine are January, February and December (Average sunshine: 7h and 18min).
Average sunshine days in September
Swansea, CA
- Average sunshine days in September: 25 days
The month with the most sunshine days is October (27.7 days).
The month with the least sunshine days is July (20 days).
Average UV index in September
Swansea, CA
- Average UV index in September: 5
The month with the highest UV index is July (UV index 7).
The months with the lowest UV index are November and December (UV index 2).
Average cloud cover in September
Swansea, CA
- Average cloud cover in September: 5
The month with the most cloud cover is January (Cloud cover 16).
The months with the least cloud cover are August and September (Cloud cover 5).
Average visibility in September
Swansea, 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).
Swansea, California, USA
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