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
The onset of September brings with it an average high-temperature of a warm 84.9°F (29.4°C), showing a negligible variation from the month before. Acton records a marked daily temperature contrast, with an average low-temperature of 60.3°F (15.7°C) during the nights of September.Heat index
The heat index value for September is appraised at 84.2°F (29°C). Long-standing exposure coupled with ongoing activity could result in exhaustion, possibly causing heat cramps.Heat index values are typically calculated for conditions of shade and a light breeze. Heat index values may surge by up to 15 Fahrenheit (8 Celsius) degrees in the presence of direct sunlight.
Note: The heat index, also known as 'real feel' or 'feels like', is a composite of temperature and humidity figures to convey how warm it feels. The individual's temperature perception can be influenced by numerous factors such as metabolic variations, physical activity, and clothing. 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
In Acton, the average relative humidity in September is 41%.Rainfall
In Acton, during September, the rain falls for 3 days and regularly aggregates up to 0.2" (5mm) of precipitation. In Acton, during the entire year, the rain falls for 51.4 days and collects up to 7.6" (193mm) of precipitation.Snowfall
May through October are months without snowfall.Daylight
In Acton, the average length of the day in September is 12h and 22min.On the first day of the month, sunrise is at 6:26 am and sunset at 7:18 pm. On the last day of September, in Acton, sunrise is at 6:47 am and sunset at 6:37 pm PDT.
Sunshine
In September, the average sunshine is 10.8h.UV index
June through September, with an average maximum UV index of 6, are months with the highest UV index. A UV Index estimate of 6 to 7 represents a high health vulnerability from unsafe exposure to UV radiation for the average person.Note: An average maximum UV index of 6 in September leads to these recommendations:
Incorporate safeguards and honour sun safety principles. Protection from skin and eye damage is obligatory. It's important to stay in the shade and limit exposure to the sun from 10 a.m. to 4 p.m., when UV radiation is most intense, although remember that shade structures may not provide full sun protection. Employ a wide-brim hat for potent defense against up to 50% of UV rays.
Published by: Weather U.S. | About Us
Data Sources | Weather Forecasting & Climate
Frequently asked questions
How hot is September in Acton?
What is the average humidity in September in Acton?
How much does it rain in Acton in September?
When it does not snow in Acton?
How many hours of daylight does Acton have in September?
When are sunrise and sunset in September in Acton?
How many hours of sunshine does Acton have in September?
What are the months with the highest UV index in Acton?
What is the UV index intensity in September in Acton?
Average temperature in September
Acton, CA
- Average high temperature in September: 84.9°F
The warmest month (with the highest average high temperature) is August (89.2°F).
The month with the lowest average high temperature is December (55.6°F).
- Average low temperature in September: 60.3°F
The month with the highest average low temperature is August (63.1°F).
The coldest month (with the lowest average low temperature) is December (39.2°F).
Average pressure in September
Acton, CA
- Average pressure in September: 29.89"Hg
The month with the highest atmospheric pressure is January (30.11"Hg).
The month with the lowest atmospheric pressure is June (29.87"Hg).
Average wind speed in September
Acton, CA
- Average wind speed in September: 5.7mph
The windiest month (with the highest average wind speed) is April (7.6mph).
The calmest month (with the lowest average wind speed) is September (5.7mph).
Average humidity in September
Acton, CA
- Average humidity in September: 41%
The months with the highest relative humidity are February, March and December (54%).
The month with the lowest relative humidity is August (38%).
Average rainfall in September
Acton, CA
- Average rainfall in September: 0.2"
The wettest month (with the highest rainfall) is December (1.65").
The driest month (with the least rainfall) is June (0.04").
Average rainfall days in September
Acton, CA
- Average rainfall days in September: 3 days
The month with the highest number of rainy days is March (7.4 days).
The month with the least rainy days is June (1.2 days).
Average snowfall in September
Acton, CA
- Average snowfall in September: 0"
The month with the highest snowfall is December (3.23").
The months with the least snowfall are May, June, July, August, September and October (0").
Average snowfall days in September
Acton, CA
- Average snowfall days in September: 0 days
The month with the highest number of snowfall days is February (0.8 days).
The months with the least snowfall days are May, June, July, August, September and October (0 days).
Average daylight in September /
Average sunshine in September
Acton, CA
- Average daylight in September: 12h and 2min
The month with the longest days is June (Average daylight: 14h and 24min).
The month with the shortest days is December (Average daylight: 9h and 54min).
- Average sunshine in September: 10h and 5min
The month with the most sunshine is July (Average sunshine: 12h and 6min).
The month with the least sunshine is January (Average sunshine: 6h and 42min).
Average sunshine days in September
Acton, CA
- Average sunshine days in September: 26.3 days
The month with the most sunshine days is June (28.3 days).
The month with the least sunshine days is February (21.3 days).
Average UV index in September
Acton, CA
- Average UV index in September: 6
The months with the highest UV index are June, July, August and September (UV index 6).
The months with the lowest UV index are January, February, November and December (UV index 3).
Average cloud cover in September
Acton, CA
- Average cloud cover in September: 6
The months with the most cloud cover are March and December (Cloud cover 24).
The month with the least cloud cover is August (Cloud cover 5).
Average visibility in September
Acton, 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).
Acton, California, USA
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