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 sea temperature 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
Alameda's warmest month, September, generally records average temperatures ranging from a high of 75.9°F (24.4°C) to a low of 56.5°F (13.6°C).Humidity
The average relative humidity in September is 66%.Rainfall
In September, the rain falls for 2.6 days. Throughout September, 0.08" (2mm) of precipitation is accumulated. Throughout the year, there are 67.2 rainfall days, and 6.1" (155mm) of precipitation is accumulated.Ocean temperature
With an average ocean temperature of 57.4°F (14.1°C), September is the month with the warmest seawater.Note: Caution: 57.4°F (14.1°C) temperatures below 50°F (10°C) during swimming can result in intense cold shock and quickened breathing.
Daylight
The average length of the day in September is 12h and 25min.On the first day of the month, sunrise is at 6:39 am and sunset at 7:37 pm. On the last day of September, sunrise is at 7:04 am and sunset at 6:52 pm PDT.
Sunshine
In Alameda, California, the average sunshine in September is 11.1h.UV index
April through September, with an average maximum UV index of 5, are months with the highest UV index. A UV Index estimate of 3 to 5 represents a moderate threat to health from exposure to the Sun's UV radiation for the average person.Note: A maximum UV index of 5 in September translates into the following recommendations:
Take necessary precautions - Suggestions to elude sunburn are provided. It's crucial to reduce time in the direct Sun around mid-day due to the intense solar radiation. Using UVA and UVB-protective sunglasses and sun-protective clothing is effective against UV radiation.
Published by: Weather U.S. | About Us
Data Sources | Weather Forecasting & Climate
Frequently asked questions
What month is the hottest?
What is the temperature in September?
What is the average humidity in September?
How many days does it rain in September?
What month is the ocean warmest?
What is the ocean temperature in September?
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?
When is the highest UV index?
How high is the UV index in September?
Average temperature in September
Alameda, CA
- Average high temperature in September: 75.9°F
The warmest month (with the highest average high temperature) is September (75.9°F).
The month with the lowest average high temperature is December (55.9°F).
- Average low temperature in September: 56.5°F
The month with the highest average low temperature is September (56.5°F).
The coldest month (with the lowest average low temperature) is January (45°F).
Average pressure in September
Alameda, 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
Alameda, CA
- Average wind speed in September: 5.4mph
The windiest month (with the highest average wind speed) is May (7.2mph).
The calmest months (with the lowest average wind speed) are October and November (5.2mph).
Average humidity in September
Alameda, CA
- Average humidity in September: 66%
The month with the highest relative humidity is March (75%).
The month with the lowest relative humidity is October (65%).
Average rainfall in September
Alameda, CA
- Average rainfall in September: 0.08"
The wettest month (with the highest rainfall) is February (1.18").
The driest month (with the least rainfall) is July (0.04").
Average rainfall days in September
Alameda, CA
- Average rainfall days in September: 2.6 days
The month with the highest number of rainy days is March (11.4 days).
The month with the least rainy days is August (1.3 days).
Average sea temperature in September
Alameda, CA
- Average sea temperature in September: 57.3°F
The best month for swimming (with the highest average sea temperature) is September (57.3°F).
The coldest months (with the lowest average sea temperature) are April and June (53°F).
Average daylight in September /
Average sunshine in September
Alameda, 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 0min).
The month with the least sunshine is December (Average sunshine: 5h and 54min).
Average sunshine days in September
Alameda, CA
- Average sunshine days in September: 24.5 days
The month with the most sunshine days is July (25.4 days).
The month with the least sunshine days is March (17.3 days).
Average UV index in September
Alameda, CA
- Average UV index in September: 5
The months with the highest UV index are April, May, June, July, August and September (UV index 5).
The months with the lowest UV index are January, November and December (UV index 3).
Average cloud cover in September
Alameda, CA
- Average cloud cover in September: 11
The month with the most cloud cover is March (Cloud cover 35).
The month with the least cloud cover is July (Cloud cover 9).
Average visibility in September
Alameda, 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).
Alameda, California, USA
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