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
The onset of September brings an average high-temperature of a still moderately hot 82°F (27.8°C), nearly matching the August temperature. Diablo, amid September nights, sees a noteworthy disparity from daily highs with an average temperature of 56.7°F (13.7°C).Heat index
The heat index in September is evaluated at 84.2°F (29°C). With prolonged exposure and constant activity, one might feel exhausted and experience heat cramps.Understanding the heat index involves considering values for shaded locales with light wind. The heat index has the potential to rise by 15 Fahrenheit (8 Celsius) degrees with direct sunshine exposure.
Note: The heat index, also known as 'felt air temperature' or 'apparent temperature', melds the effects of warmth and moisture to generate a feeling of heat. This effect is personal, influenced by the individual's physical activity and heat sensitivity, shaped by factors including wind, attire, and metabolic variations. Given the impact of direct sunlight, it's noteworthy that the felt temperature can rise by 15 Fahrenheit (8 Celsius) degrees. Heat index values are especially vital to children. Kids are usually in more danger than grown-ups as they tend to sweat less. Plus, their bigger skin surface in relation to their small frames and increased heat generation due to their activity level make them more susceptible.
Humidity
The least humid month in Diablo is September, with an average relative humidity of 57%.Rainfall
January through June, September through December are months with rainfall. September is the first month it rains in Diablo. Throughout September, in the average 1.7 rainfall days, it receives 0.08" (2mm) of precipitation. In Diablo, during the entire year, the rain falls for 65.6 days and collects up to 11.22" (285mm) 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 6:38 am and sunset at 7:36 pm. On the last day of September, in Diablo, sunrise is at 7:03 am and sunset at 6:51 pm PDT.
Sunshine
In September, the average sunshine in Diablo is 11.1h.UV index
In Diablo, the average daily maximum UV index in September is 5. A UV Index value of 3 to 5 symbolizes a medium health hazard from unsafe exposure to UV radiation for average individuals.Note: A maximum high daily UV index of 5 during September translates into the following directions:
Take precautions - Protection against sun damage is advised. The Sun's most harmful UV rays are emitted around midday; avoid staying outdoors for long during this time. Sunglasses that ward off UVA and UVB rays play a pivotal role in reducing solar eye damage.
Frequently asked questions
What is the usual temperature for Diablo in September?
What is the least humid month in Diablo?
What is the average humidity in September in Diablo?
When does it start raining in Diablo?
What is the average length of the day in September in Diablo?
When are sunrise and sunset in September in Diablo?
How long on average sun shines in September in Diablo?
What is the UV index reading in September in Diablo?
Average temperature in September
Diablo, CA
- Average high temperature in September: 82°F
The warmest month (with the highest average high temperature) is July (83.8°F).
The month with the lowest average high temperature is December (55.8°F).
- Average low temperature in September: 56.7°F
The months with the highest average low temperature are August and September (56.7°F).
The coldest month (with the lowest average low temperature) is January (42.1°F).
Average pressure in September
Diablo, 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
Diablo, CA
- Average wind speed in September: 5.4mph
The windiest month (with the highest average wind speed) is May (6.9mph).
The calmest month (with the lowest average wind speed) is November (4.3mph).
Average humidity in September
Diablo, CA
- Average humidity in September: 57%
The month with the highest relative humidity is March (74%).
The month with the lowest relative humidity is September (57%).
Average rainfall in September
Diablo, CA
- Average rainfall in September: 0.08"
The wettest month (with the highest rainfall) is February (2.36").
The driest months (with the least rainfall) are July and August (0").
Average rainfall days in September
Diablo, CA
- Average rainfall days in September: 1.7 days
The month with the highest number of rainy days is March (12.6 days).
The month with the least rainy days is August (0.6 days).
Average daylight in September /
Average sunshine in September
Diablo, 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: 11h and 1min
The month with the most sunshine is July (Average sunshine: 12h and 6min).
The month with the least sunshine is December (Average sunshine: 5h and 48min).
Average sunshine days in September
Diablo, CA
- Average sunshine days in September: 27.2 days
The month with the most sunshine days is July (30.2 days).
The month with the least sunshine days is March (17.6 days).
Average UV index in September
Diablo, 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
Diablo, CA
- Average cloud cover in September: 10
The month with the most cloud cover is March (Cloud cover 36).
The month with the least cloud cover is July (Cloud cover 6).
Average visibility in September
Diablo, 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).
Diablo, California, USA
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