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 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 advent of September denotes an average high-temperature of a moderately hot 85.3°F (29.6°C), subtly different from August's 87.4°F (30.8°C). September presents a pronounced divergence from daily peak temperatures, with the average low-temperature of 57.7°F (14.3°C).Heat index
For most parts of September, the heat index is computed to be a tropical 87.8°F (31°C). When exposure and activity are sustained, they could induce fatigue, with a chance of heat cramps.It is important to note that the heat index values are for shaded areas and light wind scenarios. Exposure to direct sunlight may make the heat index values climb by 15 Fahrenheit (8 Celsius) degrees.
Note: The heat index, also known as 'real feel' or 'feels like', provides an understanding of perceived warmth by combining temperature and relative humidity. This effect is personal, shaped by the individual's physical activity and heat sensitivity, influenced by factors including wind, clothing, and metabolic variances. In direct sunlight, the heat's impact can be heightened, potentially leading to an increase in the heat index by 15 Fahrenheit (8 Celsius) degrees. Heat index values are particularly meaningful for babies and toddlers. Kids are usually in more danger than grown-ups as they tend to sweat less. Plus, their bigger skin surface in relation to their small frames and increased heat generation due to their activity level make them more susceptible.
Humidity
September is the least humid month in Bethel Island, with an average relative humidity of 52%.Rainfall
In Bethel Island, California, during September, the rain falls for 1.3 days and regularly aggregates up to 0.08" (2mm) of precipitation. In Bethel Island, during the entire year, the rain falls for 62 days and collects up to 10.16" (258mm) of precipitation.Snowfall
January through November are months without snowfall.Daylight
The average length of the day in September is 12h and 25min.On the first day of the month, sunrise is at 6:37 am and sunset at 7:35 pm. On the last day of September, sunrise is at 7:02 am and sunset at 6:50 pm PDT.
Sunshine
In September, the average sunshine is 11.2h.UV index
The average daily maximum UV index in September is 5. A UV Index reading of 3 to 5 represents a moderate health risk from exposure to the Sun's UV radiation for average individuals.Note: In September, a regular UV index of 5 translates into these guidelines:
Heed the precautions - Protecting the skin and eyes from damage is compulsory. For health reasons, it's advisable to reduce direct sun exposure during peak hours around midday. In bright sunlight, prioritize sunglasses that grant protection from UVA and UVB radiation.
Published by: Weather U.S. | About Us
Data Sources | Weather Forecasting & Climate
Frequently asked questions
How hot is September?
What is the least humid month?
What is the average humidity in September?
How much does it rain in September?
When it does not snow?
What is the average length of the day in September?
When is the sunrise / sunset in September?
How long on average sun shines in September?
What is the UV index intensity in September?
Average temperature in September
Bethel Island, CA
- Average high temperature in September: 85.3°F
The warmest month (with the highest average high temperature) is July (88.5°F).
The month with the lowest average high temperature is December (55°F).
- Average low temperature in September: 57.7°F
The month with the highest average low temperature is September (57.7°F).
The coldest month (with the lowest average low temperature) is January (41.5°F).
Average pressure in September
Bethel Island, 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
Bethel Island, CA
- Average wind speed in September: 6.2mph
The windiest month (with the highest average wind speed) is June (7.8mph).
The calmest months (with the lowest average wind speed) are January and November (4.5mph).
Average humidity in September
Bethel Island, CA
- Average humidity in September: 52%
The month with the highest relative humidity is January (74%).
The month with the lowest relative humidity is September (52%).
Average rainfall in September
Bethel Island, CA
- Average rainfall in September: 0.08"
The wettest month (with the highest rainfall) is February (2.09").
The driest months (with the least rainfall) are July and August (0.04").
Average rainfall days in September
Bethel Island, CA
- Average rainfall days in September: 1.3 days
The month with the highest number of rainy days is March (12.3 days).
The month with the least rainy days is August (0.8 days).
Average snowfall days in September
Bethel Island, 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
Bethel Island, 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 6min).
The month with the least sunshine is December (Average sunshine: 5h and 48min).
Average sunshine days in September
Bethel Island, CA
- Average sunshine days in September: 28.5 days
The month with the most sunshine days is August (29.8 days).
The month with the least sunshine days is March (17.7 days).
Average UV index in September
Bethel Island, CA
- Average UV index in September: 5
The months with the highest UV index are June, July and August (UV index 6).
The months with the lowest UV index are January, February, November and December (UV index 3).
Average cloud cover in September
Bethel Island, CA
- Average cloud cover in September: 8
The months with the most cloud cover are March and December (Cloud cover 35).
The month with the least cloud cover is July (Cloud cover 5).
Average visibility in September
Bethel Island, 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).
Bethel Island, California, USA
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