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 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
In Half Moon Bay, September is the month with the highest recorded average temperatures, measuring a high of 66.9°F (19.4°C) and a low of 56.7°F (13.7°C).Humidity
In Half Moon Bay, the average relative humidity in September is 77%.Rainfall
In Half Moon Bay, California, in September, it is raining for 3.6 days, with typically 0.16" (4mm) of accumulated precipitation. In Half Moon Bay, during the entire year, the rain falls for 76.8 days and collects up to 8.54" (217mm) of precipitation.Daylight
In September, the average length of the day 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, in Half Moon Bay, California, sunrise is at 7:05 am and sunset at 6:53 pm PDT.
Sunshine
In September, the average sunshine in Half Moon Bay is 10.7h.UV index
The months with the highest UV index are June, August and September, with an average maximum UV index of 5. A UV Index of 3 to 5 symbolizes a medium health hazard from unprotected exposure to Sun's UV rays for average individuals.Note: A maximum daily UV index of 5 during September morphs into the following directions:
Be careful. Light complexion individuals might get burns in fewer than 30 minutes. Considering the harmful UV rays from the Sun during midday, it's essential to reduce exposure. On bright days sunglasses that block both UVA and UVB rays should be worn. A hat with a wide brim is extremely helpful, as it can prevent roughly 50% of UV radiation from reaching the eyes.
Frequently asked questions
What are the warmest months in Half Moon Bay?
What is the usual temperature for Half Moon Bay in September?
What is the average humidity in September in Half Moon Bay?
How much does it rain in Half Moon Bay in September?
How many hours of daylight does Half Moon Bay have in September?
When is the sunrise / sunset in September in Half Moon Bay?
How long on average sun shines in September in Half Moon Bay?
What is the month with the highest UV index in Half Moon Bay?
What is the UV index intensity in September in Half Moon Bay?
Average temperature in September
Half Moon Bay, CA
- Average high temperature in September: 66.9°F
The warmest month (with the highest average high temperature) is September (66.9°F).
The month with the lowest average high temperature is December (55.6°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 February (48.7°F).
Average pressure in September
Half Moon Bay, 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
Half Moon Bay, CA
- Average wind speed in September: 7mph
The windiest month (with the highest average wind speed) is April (9.6mph).
The calmest month (with the lowest average wind speed) is August (6.6mph).
Average humidity in September
Half Moon Bay, CA
- Average humidity in September: 77%
The month with the highest relative humidity is August (82%).
The months with the lowest relative humidity are November and December (72%).
Average rainfall in September
Half Moon Bay, CA
- Average rainfall in September: 0.16"
The wettest month (with the highest rainfall) is February (1.61").
The driest months (with the least rainfall) are June and July (0.12").
Average rainfall days in September
Half Moon Bay, CA
- Average rainfall days in September: 3.6 days
The month with the highest number of rainy days is March (10.8 days).
The month with the least rainy days is June (3 days).
Average daylight in September /
Average sunshine in September
Half Moon Bay, 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: 10h and 4min
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
Half Moon Bay, CA
- Average sunshine days in September: 22.6 days
The month with the most sunshine days is October (24.6 days).
The months with the least sunshine days are March and August (18.8 days).
Average UV index in September
Half Moon Bay, CA
- Average UV index in September: 5
The months with the highest UV index are June, August and September (UV index 5).
The months with the lowest UV index are January, February, March, April, May, July, October, November and December (UV index 4).
Average cloud cover in September
Half Moon Bay, 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
Half Moon Bay, 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).
Half Moon Bay, California, USA
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