September weather forecastBelmont, CA
September
Weather in September
September, the first month of the autumn in Belmont, is also an agreeable month, with an average temperature varying between 72.9°F (22.7°C) and 56.7°F (13.7°C).Temperature
In September, Belmont experiences a barely noticeable shift in meteorological conditions, with average high-temperatures moving from 73°F (22.8°C) in August to a still agreeable 72.9°F (22.7°C). In Belmont, an average nighttime temperature of 56.7°F (13.7°C) is expected during September.Humidity
The average relative humidity in September is 69%.Rainfall
In Belmont, in September, during 2.8 rainfall days, 0.16" (4mm) of precipitation is typically accumulated. Throughout the year, there are 77.5 rainfall days, and 11.22" (285mm) of precipitation is accumulated.Daylight
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 7:37 pm. On the last day of September, sunrise is at 7:04 am and sunset at 6:53 pm PDT.
Sunshine
In Belmont, the average sunshine in September is 11h.UV index
The months with the highest UV index are June through September, with an average maximum UV index of 5. A UV Index reading of 3 to 5 represents a medium vulnerability from exposure to the Sun's UV radiation for average individuals.Note: The UV index of 5 during September leads to these advisories:
Adopt protective measures - Requirement to safeguard skin and eyes from harm exists. The Sun's radiation is especially intense around midday; try to stay in shade during this period. 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
Average temperature in September
Belmont, CA
- Average high temperature in September: 72.9°F
The warmest month (with the highest average high temperature) is August (73°F).
The month with the lowest average high temperature is December (55.9°F).
- Average low temperature in September: 56.7°F
The month with the highest average low temperature is September (56.7°F).
The coldest month (with the lowest average low temperature) is January (46°F).
Average pressure in September
Belmont, CA
- Average pressure in September: 29.92"Hg
The month with the highest atmospheric pressure is January (30.13"Hg).
The month with the lowest atmospheric pressure is September (29.92"Hg).
Average wind speed in September
Belmont, CA
- Average wind speed in September: 5.6mph
The windiest month (with the highest average wind speed) is April (7.5mph).
The calmest month (with the lowest average wind speed) is October (5.5mph).
Average humidity in September
Belmont, CA
- Average humidity in September: 69%
The month with the highest relative humidity is March (75%).
The month with the lowest relative humidity is October (68%).
Average rainfall in September
Belmont, CA
- Average rainfall in September: 0.16"
The wettest month (with the highest rainfall) is February (2.09").
The driest months (with the least rainfall) are July and August (0.08").
Average rainfall days in September
Belmont, CA
- Average rainfall days in September: 2.8 days
The month with the highest number of rainy days is March (13 days).
The month with the least rainy days is July (1.8 days).
Average daylight in September /
Average sunshine in September
Belmont, 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: 11h and 0min
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 48min).
Average sunshine days in September
Belmont, CA
- Average sunshine days in September: 23.9 days
The month with the most sunshine days is July (25.3 days).
The month with the least sunshine days is March (16.3 days).
Average UV index in September
Belmont, CA
- Average UV index in September: 5
The months with the highest UV index are June, July, August and September (UV index 5).
The months with the lowest UV index are February, November and December (UV index 3).
Average cloud cover in September
Belmont, CA
- Average cloud cover in September: 12
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
Belmont, 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).
