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 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
O'Brien's progression into September involves a gentle drop in the average high-temperature, from a hot 90.1°F (32.3°C) in August to a warm 84°F (28.9°C). A significant temperature decrease to an average a cool 54.3°F (12.4°C) characterizes O'Brien's nighttime temperatures during September.Heat index
The average heat index in September is computed to be 84.2°F (29°C). With extended exposure and activity, one might feel exhausted and experience heat cramps.In the scope of the heat index, its values resonate with shade and light wind conditions. Direct sunlight exposure may result in a rise of the heat index by 15 Fahrenheit (8 Celsius) degrees.
Note: The heat index, also known as 'felt air temperature' or 'apparent temperature', integrates the air's temperature and its humidity to showcase the felt temperature by people. This impact is subjective, influenced by the person's physical activity and individual heat perception, affected by factors including wind, attire, and metabolic differences. By being directly under the sun, it's possible for the felt temperature to increase by 15 Fahrenheit (8 Celsius) degrees. Heat index values are highly critical to babies and toddlers. Typically, children face more danger than adults as they usually perspire less. Their larger skin surface relative to their small bodies and increased heat output from their activities enhance their risk.
Humidity
The average relative humidity in September in O'Brien is 40%.Rainfall
In O'Brien, California, in September, it is raining for 3.4 days, with typically 0.31" (8mm) of accumulated precipitation. Throughout the year, there are 102.3 rainfall days, and 24.21" (615mm) of precipitation is accumulated.Snowfall
In O'Brien, snow does not fall in April through October.Daylight
In O'Brien, the average length of the day in September is 12h and 27min.On the first day of September, sunrise is at 6:37 am and sunset at 7:41 pm. On the last day of the month, sunrise is at 7:05 am and sunset at 6:52 pm PDT.
Sunshine
In O'Brien, the average sunshine in September is 11h.UV index
The average daily maximum UV index in September in O'Brien is 5. A UV Index of 3 to 5 symbolizes a medium vulnerability from exposure to the Sun's UV radiation for the ordinary person.Note: The UV index of 5 during September leads to these advisories:
Undertake protective steps - Obligation to safeguard skin and eyes from harm is in place. Avoiding the Sun during its peak radiation time around midday is a healthy practice. For optimum UV protection, wear sun-resistant attire complemented with a hat and quality shades.
Frequently asked questions
How hot is it in O'Brien in September?
What is the average humidity in September in O'Brien?
How many days does it rain in September in O'Brien?
When it does not snow in O'Brien?
How many hours of daylight does O'Brien have in September?
When are sunrise and sunset in September in O'Brien?
How many hours of sunshine does O'Brien have in September?
What is the UV index reading in September in O'Brien?
Average temperature in September
O'Brien, CA
- Average high temperature in September: 84°F
The warmest month (with the highest average high temperature) is July (91.6°F).
The month with the lowest average high temperature is December (47.8°F).
- Average low temperature in September: 54.3°F
The month with the highest average low temperature is July (59.4°F).
The coldest month (with the lowest average low temperature) is December (33.6°F).
Average pressure in September
O'Brien, CA
- Average pressure in September: 29.95"Hg
The month with the highest atmospheric pressure is January (30.16"Hg).
The month with the lowest atmospheric pressure is August (29.92"Hg).
Average wind speed in September
O'Brien, CA
- Average wind speed in September: 5mph
The windiest months (with the highest average wind speed) are March and October (5.3mph).
The calmest months (with the lowest average wind speed) are August and November (4.5mph).
Average humidity in September
O'Brien, CA
- Average humidity in September: 40%
The month with the highest relative humidity is March (77%).
The month with the lowest relative humidity is August (37%).
Average rainfall in September
O'Brien, CA
- Average rainfall in September: 0.31"
The wettest month (with the highest rainfall) is March (4.8").
The driest month (with the least rainfall) is July (0.12").
Average rainfall days in September
O'Brien, CA
- Average rainfall days in September: 3.4 days
The month with the highest number of rainy days is March (16.8 days).
The month with the least rainy days is August (1.7 days).
Average snowfall in September
O'Brien, CA
- Average snowfall in September: 0"
The month with the highest snowfall is November (1.3").
The months with the least snowfall are April, May, June, July, August, September and October (0").
Average snowfall days in September
O'Brien, CA
- Average snowfall days in September: 0 days
The month with the highest number of snowfall days is February (1.9 days).
The months with the least snowfall days are April, May, June, July, August, September and October (0 days).
Average daylight in September /
Average sunshine in September
O'Brien, CA
- Average daylight in September: 12h and 2min
The month with the longest days is June (Average daylight: 15h and 6min).
The month with the shortest days is December (Average daylight: 9h and 18min).
- Average sunshine in September: 11h and 0min
The month with the most sunshine is July (Average sunshine: 12h and 12min).
The month with the least sunshine is December (Average sunshine: 5h and 18min).
Average sunshine days in September
O'Brien, CA
- Average sunshine days in September: 25.2 days
The month with the most sunshine days is August (27.1 days).
The month with the least sunshine days is March (11.8 days).
Average UV index in September
O'Brien, CA
- Average UV index in September: 5
The month with the highest UV index is July (UV index 7).
The months with the lowest UV index are February, November and December (UV index 2).
Average cloud cover in September
O'Brien, CA
- Average cloud cover in September: 9
The month with the most cloud cover is March (Cloud cover 44).
The month with the least cloud cover is August (Cloud cover 5).
Average visibility in September
O'Brien, CA
- Average visibility in September: 6mi
The months with the highest visibility are January, February, March, April, May, June, July, August, September, October and November (6mi).
The month with the lowest visibility is December (5mi).
O'Brien, California, USA
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