September weather forecastBelvedere, CA
September
Weather in September
The first month of the autumn, September, is also an agreeable month in Belvedere, California, with an average temperature fluctuating between 72.3°F (22.4°C) and 56.5°F (13.6°C).Temperature
With average temperatures fluctuating between a high of 72.3°F (22.4°C) and a low of 56.5°F (13.6°C), September stands out as the warmest month.Humidity
In Belvedere, the average relative humidity in September is 71%.Rainfall
June through September are months with the least rain when the rain falls for 2.7 days and typically aggregates up to 0.08" (2mm) of rain.Ocean temperature
September is the month with the warmest seawater, with an average ocean temperature of 57.4°F (14.1°C).Note: With an efficient thermal swimsuit, one can navigate 57.4°F (14.1°C) even if it's colder than 50°F (10°C); otherwise, rapid cold shock and breathlessness might set in. Barely wading at 55.4°F (13°C) feels chilly.
Daylight
In Belvedere, the average length of the day in September is 12h and 25min.On the first day of the month, sunrise is at 6:40 am and sunset at 7:38 pm. On the last day of September, sunrise is at 7:05 am and sunset at 6:53 pm PDT.
Sunshine
In September, the average sunshine is 10.6h.UV index
The months with the highest UV index in Belvedere are April, June through September, with an average maximum UV index of 5. A UV Index reading of 3 to 5 represents a moderate threat to health from exposure to the Sun's UV rays for the ordinary person.Note: A maximum high daily UV index of 5 during September translates into the following directions:
Take necessary precautions - Protection from skin and eye injury is mandatory. Solar radiation is at its peak intensity during midday, so it's advisable to stay indoors or in the shade. Equip yourself with UVA and UVB-filtering sunglasses on clear, sunny days.
Published by: Weather U.S. | About Us
Data Sources | Weather Forecasting & Climate
Frequently asked questions
Average temperature in September
Belvedere, CA
- Average high temperature in September: 72.3°F
The warmest month (with the highest average high temperature) is September (72.3°F).
The month with the lowest average high temperature is December (55.2°F).
- Average low temperature in September: 56.5°F
The month with the highest average low temperature is September (56.5°F).
The coldest months (with the lowest average low temperature) are January and December (46.2°F).
Average pressure in September
Belvedere, 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
Belvedere, CA
- Average wind speed in September: 5.9mph
The windiest month (with the highest average wind speed) is May (7.9mph).
The calmest months (with the lowest average wind speed) are October and November (5.7mph).
Average humidity in September
Belvedere, CA
- Average humidity in September: 71%
The months with the highest relative humidity are March and August (76%).
The month with the lowest relative humidity is October (68%).
Average rainfall in September
Belvedere, CA
- Average rainfall in September: 0.08"
The wettest month (with the highest rainfall) is February (0.98").
The driest months (with the least rainfall) are June, July, August and September (0.08").
Average rainfall days in September
Belvedere, CA
- Average rainfall days in September: 2.7 days
The month with the highest number of rainy days is March (10.5 days).
The month with the least rainy days is June (1.9 days).
Average sea temperature in September
Belvedere, 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
Belvedere, CA
- Average daylight in September: 12h and 24min
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: 10h and 36min
The month with the most sunshine is July (Average sunshine: 11h and 24min).
The month with the least sunshine is December (Average sunshine: 5h and 42min).
Average sunshine days in September
Belvedere, CA
- Average sunshine days in September: 24.5 days
The month with the most sunshine days is October (25 days).
The month with the least sunshine days is March (18.4 days).
Average UV index in September
Belvedere, CA
- Average UV index in September: 5
The months with the highest UV index are April, June, July, August and September (UV index 5).
The months with the lowest UV index are January, February, November and December (UV index 3).
Average cloud cover in September
Belvedere, CA
- Average cloud cover in September: 18
The month with the most cloud cover is March (Cloud cover 38).
The month with the least cloud cover is September (Cloud cover 18).
Average visibility in September
Belvedere, 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).
