September weather forecastTwain, CA
September
Weather in September
The first month of the autumn, September, is also a moderately hot month in Twain, California, with an average temperature varying between 75°F (23.9°C) and 43.9°F (6.6°C).Temperature
The transition to September results in a modest reduction in average high-temperature, moving from a warm 82.9°F (28.3°C) in August to a still moderately hot 75°F (23.9°C). Twain observes a distinct decrease from peak daytime temperatures, with an average low-temperature of 43.9°F (6.6°C) throughout the month of September.Humidity
In Twain, the average relative humidity in September is 47%.Rainfall
In Twain, during September, the rain falls for 4.1 days and regularly aggregates up to 0.39" (10mm) of precipitation. In Twain, during the entire year, the rain falls for 91.7 days and collects up to 23.19" (589mm) of precipitation.Snowfall
In Twain, California, snow does not fall in June through September.Daylight
The average length of the day in September is 12h and 26min.On the first day of September in Twain, sunrise is at 6:32 am and sunset at 7:35 pm. On the last day of the month, sunrise is at 7:00 am and sunset at 6:47 pm PDT.
Sunshine
In Twain, California, the average sunshine in September is 11.2h.UV index
The average daily maximum UV index in September is 4. A UV Index estimate of 3 to 5 represents a moderate threat to health from exposure to the Sun's UV rays for average individuals.Note: A daily maximum UV index of 4 in September translates into the following instructions:
Undertake protective steps - Obligation to safeguard skin and eyes from harm is in place. The solar radiation around mid-day is intense; avoid the Sun and stay safe. Wearing sunglasses with both UVA and UVB protection effectively reduces sun-induced eye damage.
Published by: Weather U.S. | About Us
Data Sources | Weather Forecasting & Climate
Frequently asked questions
Average temperature in September
Twain, CA
- Average high temperature in September: 75°F
The warmest month (with the highest average high temperature) is July (83.1°F).
The month with the lowest average high temperature is December (39.2°F).
- Average low temperature in September: 43.9°F
The month with the highest average low temperature is July (49.1°F).
The coldest month (with the lowest average low temperature) is December (23.4°F).
Average pressure in September
Twain, CA
- Average pressure in September: 29.93"Hg
The month with the highest atmospheric pressure is January (30.19"Hg).
The month with the lowest atmospheric pressure is June (29.9"Hg).
Average wind speed in September
Twain, CA
- Average wind speed in September: 5mph
The windiest month (with the highest average wind speed) is March (6.4mph).
The calmest month (with the lowest average wind speed) is August (4.7mph).
Average humidity in September
Twain, CA
- Average humidity in September: 47%
The months with the highest relative humidity are January and March (81%).
The month with the lowest relative humidity is July (41%).
Average rainfall in September
Twain, CA
- Average rainfall in September: 0.39"
The wettest months (with the highest rainfall) are February and December (4.06").
The driest month (with the least rainfall) is July (0.12").
Average rainfall days in September
Twain, CA
- Average rainfall days in September: 4.1 days
The month with the highest number of rainy days is March (13.3 days).
The month with the least rainy days is August (1.8 days).
Average snowfall in September
Twain, CA
- Average snowfall in September: 0"
The month with the highest snowfall is February (13.07").
The months with the least snowfall are June, July, August and September (0").
Average snowfall days in September
Twain, CA
- Average snowfall days in September: 0 days
The month with the highest number of snowfall days is March (8.5 days).
The months with the least snowfall days are June, July, August and September (0 days).
Average daylight in September /
Average sunshine in September
Twain, CA
- Average daylight in September: 12h and 24min
The month with the longest days is June (Average daylight: 15h and 0min).
The month with the shortest days is December (Average daylight: 9h and 24min).
- Average sunshine in September: 11h and 12min
The month with the most sunshine is July (Average sunshine: 12h and 6min).
The month with the least sunshine is January (Average sunshine: 5h and 24min).
Average sunshine days in September
Twain, CA
- Average sunshine days in September: 25.6 days
The month with the most sunshine days is August (27.8 days).
The month with the least sunshine days is March (12.3 days).
Average UV index in September
Twain, CA
- Average UV index in September: 4
The month with the highest UV index is July (UV index 6).
The months with the lowest UV index are January, February, March, November and December (UV index 2).
Average cloud cover in September
Twain, CA
- Average cloud cover in September: 11
The month with the most cloud cover is March (Cloud cover 45).
The months with the least cloud cover are July and August (Cloud cover 6).
Average visibility in September
Twain, CA
- Average visibility in September: 6mi
The months with the highest visibility are April, May, June, July, August, September, October and November (6mi).
The months with the lowest visibility are January, February, March and December (5mi).





