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 September, the average high-temperature is practically the same as in August - a still moderately hot 82.9°F (28.3°C). In Livermore, in September, the average low-temperature is 56.5°F (13.6°C).Heat index
The average heat index in September is calculated to be 84.2°F (29°C). Constant exposure and activity lead to possible fatigue. Prolonged exercise may result in heat cramps.Note that heat index values are valued for light wind and location in the shade. Exposure to direct sunshine can increase heat index values by up to 15 Fahrenheit (8 Celsius) degrees.
Note: The heat index, also known as 'apparent temperature', 'feels like', 'real feel', or 'felt air temperature', is a calculated temperature value of how hot it feels when the moisture in the air is factored in. This effect is subjective, depending on the activity and individual's heat perception influenced by various reasons (differences in body mass, height, and shape, pregnancy, metabolic differences). Be aware that direct exposure to sunlight increases heat impact and may raise the heat index by up to 15 Fahrenheit (8 Celsius) degrees. Heat index values are especially crucial for babies and toddlers. Young children are generally more endangered than adults, as they usually less sweat. And also, due to larger skin surface relative to their small bodies and higher heat production as a result of their activity.
Humidity
July and September, with an average relative humidity of 55%, are the least humid months.Rainfall
In Livermore, during 2.3 rainfall days, 0.16" (4mm) of precipitation is typically accumulated. Throughout the year, in Livermore, there are 70.6 rainfall days, and 11.3" (287mm) of precipitation is accumulated.Daylight
In Livermore, California, the average length of the day in September is 12h and 25min.On the first day of the month, sunrise is at 6:37 am and sunset at 7:36 pm. On the last day of September, in Livermore, sunrise is at 7:01 am and sunset at 6:52 pm PDT.
Sunshine
In Livermore, the average sunshine in September is 11.3h.UV index
In September, the average daily maximum UV index is 5. A UV Index reading of 3 to 5 represents a medium health hazard from unsafe exposure to UV radiation for average individuals.Note: In September, the average maximum UV index of 5 translate into the following recommendations:
Take precautions. Light skin individuals may get burned in less than 30 minutes. The Sun's most intense and consequently most harmful UV radiation during midday hours should be decreased by minimizing exposure and seeking shade. A wide-brim hat offers excellent sun protection for the eyes, ears, face, and neck. Sunglasses with UVA and UVB protection significantly reduce eye damage from sun exposure. Tightly woven, loose-fitting clothes provide additional protection from the Sun.
FAQ
What is the temperature in September in Livermore?
What are the least humid months in Livermore?
What is the average humidity in September in Livermore?
How many days does it rain in September in Livermore?
How many hours of daylight does Livermore have in September?
When is the sunrise / sunset in September in Livermore?
How long on average sun shines in September in Livermore?
What is the UV index intensity in September in Livermore?
Average temperature in September
Livermore, CA
- Average high temperature in September: 82.9°F
The warmest month (with the highest average high temperature) is July (86°F).
The month with the lowest average high temperature is December (54.9°F).
- Average low temperature in September: 56.5°F
The month with the highest average low temperature is August (56.7°F).
The coldest month (with the lowest average low temperature) is January (41.4°F).
Average pressure in September
Livermore, CA
- Average pressure in September: 29.92"Hg
The month with the highest atmospheric pressure is January (30.14"Hg).
The months with the lowest atmospheric pressure are June, August and September (29.92"Hg).
Average wind speed in September
Livermore, CA
- Average wind speed in September: 5.2mph
The windiest months (with the highest average wind speed) are May and June (6.5mph).
The calmest month (with the lowest average wind speed) is November (4.2mph).
Average humidity in September
Livermore, CA
- Average humidity in September: 55%
The month with the highest relative humidity is March (74%).
The months with the lowest relative humidity are July and September (55%).
Average rainfall in September
Livermore, CA
- Average rainfall in September: 0.16"
The wettest month (with the highest rainfall) is February (2.09").
The driest month (with the least rainfall) is August (0.04").
Average rainfall days in September
Livermore, CA
- Average rainfall days in September: 2.3 days
The month with the highest number of rainy days is March (12.7 days).
The month with the least rainy days is August (1.3 days).
Average daylight in September /
Average sunshine in September
Livermore, CA
- Average daylight in September: 12h and 25min
The month with the longest days is June (Average daylight: 14h and 44min).
The month with the shortest days is December (Average daylight: 9h and 37min).
- Average sunshine in September: 11h and 18min
The month with the most sunshine is July (Average sunshine: 12h and 6min).
The month with the least sunshine is December (Average sunshine: 6h and 0min).
Average sunshine days in September
Livermore, CA
- Average sunshine days in September: 26.5 days
The month with the most sunshine days is August (28.8 days).
The month with the least sunshine days is March (17.6 days).
Average UV index in September
Livermore, CA
- Average UV index in September: 5
The months with the highest UV index are June, July and August (UV index 6).
The months with the lowest UV index are January, February, November and December (UV index 3).
Average cloud cover in September
Livermore, CA
- Average cloud cover in September: 9
The month with the most cloud cover is March (Cloud cover 35).
The month with the least cloud cover is July (Cloud cover 5).
Average visibility in September
Livermore, 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).
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