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 results in a small decrease in the average high-temperature, moderately receding from a moderately hot 84.9°F (29.4°C) in August to a still warm 79.3°F (26.3°C). In Arnold, the average temperature during the nights of September marks a significant drop from the daily high, settling at a fresh 53.4°F (11.9°C).Humidity
The average relative humidity in September is 39%.Rainfall
In Arnold, California, during September, the rain falls for 2.5 days and regularly aggregates up to 0.2" (5mm) of precipitation. Throughout the year, there are 69 rainfall days, and 29.09" (739mm) of precipitation is accumulated.Snowfall
June through September are months without snowfall.Daylight
In September, the average length of the day is 12h and 25min.On the first day of September, sunrise is at 6:31 am and sunset at 7:30 pm. On the last day of the month, sunrise is at 6:56 am and sunset at 6:45 pm PDT.
Sunshine
In September, the average sunshine is 11.3h.UV index
The average daily maximum UV index in September is 4. A UV Index of 3 to 5 symbolizes a medium vulnerability from unsafe exposure to UV radiation for average individuals.Note: A maximum high UV index of 4 in September translates into the following recommendations:
Take precautions - Protection against sunburn is recommended. Around midday, solar radiation is most harmful; hence, exposure should be limited. Sunglasses that ward off UVA and UVB rays play a pivotal role in reducing solar eye damage. Be prepared! The intensity of the Sun's UV radiation can be amplified nearly double due to snow reflection.
Published by: Weather U.S. | About Us
Data Sources | Weather Forecasting & Climate
Frequently asked questions
What is the average September temperature?
What is the average humidity in September?
How much does it rain in September?
When it does not snow?
Does it snow in September?
What is the average length of the day in September?
When is the sunrise / sunset in September?
How long on average sun shines in September?
What is the UV index reading in September?
Average temperature in September
Arnold, CA
- Average high temperature in September: 79.3°F
The warmest month (with the highest average high temperature) is July (85.8°F).
The month with the lowest average high temperature is December (48°F).
- Average low temperature in September: 53.4°F
The month with the highest average low temperature is July (57.2°F).
The coldest month (with the lowest average low temperature) is December (32°F).
Average pressure in September
Arnold, CA
- Average pressure in September: 29.93"Hg
The month with the highest atmospheric pressure is January (30.16"Hg).
The month with the lowest atmospheric pressure is June (29.91"Hg).
Average wind speed in September
Arnold, CA
- Average wind speed in September: 5.2mph
The windiest month (with the highest average wind speed) is February (6.1mph).
The calmest month (with the lowest average wind speed) is August (4.8mph).
Average humidity in September
Arnold, CA
- Average humidity in September: 39%
The month with the highest relative humidity is March (74%).
The month with the lowest relative humidity is July (36%).
Average rainfall in September
Arnold, CA
- Average rainfall in September: 0.2"
The wettest month (with the highest rainfall) is March (5.98").
The driest months (with the least rainfall) are July and August (0.08").
Average rainfall days in September
Arnold, CA
- Average rainfall days in September: 2.5 days
The month with the highest number of rainy days is March (11.3 days).
The month with the least rainy days is August (1.6 days).
Average snowfall in September
Arnold, CA
- Average snowfall in September: 0"
The month with the highest snowfall is March (21.34").
The months with the least snowfall are June, July, August and September (0").
Average snowfall days in September
Arnold, CA
- Average snowfall days in September: 0.1 days
The month with the highest number of snowfall days is March (7.2 days).
The months with the least snowfall days are June, July and August (0 days).
Average daylight in September /
Average sunshine in September
Arnold, CA
- Average daylight in September: 12h and 2min
The month with the longest days is June (Average daylight: 14h and 48min).
The month with the shortest days is December (Average daylight: 9h and 36min).
- Average sunshine in September: 11h and 2min
The month with the most sunshine is July (Average sunshine: 12h and 12min).
The month with the least sunshine is December (Average sunshine: 6h and 0min).
Average sunshine days in September
Arnold, CA
- Average sunshine days in September: 26.2 days
The month with the most sunshine days is August (27.9 days).
The month with the least sunshine days is March (14.5 days).
Average UV index in September
Arnold, CA
- Average UV index in September: 4
The months with the highest UV index are June, July and August (UV index 6).
The months with the lowest UV index are February, November and December (UV index 2).
Average cloud cover in September
Arnold, CA
- Average cloud cover in September: 7
The month with the most cloud cover is March (Cloud cover 37).
The months with the least cloud cover are July and August (Cloud cover 5).
Average visibility in September
Arnold, 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).
Arnold, California, USA
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