December weather forecastSimi Valley, CA
December
Weather in December
The first month of the winter, December, is also a moderate month in Simi Valley, California, with an average temperature varying between 46.4°F (8°C) and 60.1°F (15.6°C).Temperature
In Simi Valley, December is the month with the lowest recorded average temperatures, measuring a high of 60.1°F (15.6°C) and a low of 46.4°F (8°C).Humidity
The average relative humidity in December is 55%.Rainfall
In December, the rain falls for 6.4 days. Throughout December, 1.69" (43mm) of precipitation is accumulated. In Simi Valley, during the entire year, the rain falls for 53.7 days and collects up to 9.61" (244mm) of precipitation.Daylight
With an average of 9h and 54min of daylight, December has the shortest days of the year.On the first day of the month, sunrise is at 6:43 am and sunset at 4:45 pm. On the last day of December, sunrise is at 7:01 am and sunset at 4:55 pm PST.
Sunshine
The months with the least sunshine are January, February and December, with an average of 6.8h of sunshine.UV index
December is the month with the lowest UV index, with an average maximum UV index of 3. A UV Index estimate of 3 to 5 represents a moderate threat to health from unprotected exposure to Sun's UV rays for ordinary individuals.Note: The maximum daily UV index of 3 during December translates into the following directions:
Undertake protective steps - Preventing sun damage is advised. Stay safe from the Sun's strongest UV rays by limiting exposure during midday. Sun-related eye harm can be minimized with proper sunglasses offering UVA and UVB coverage.
Published by: Weather U.S. | About Us
Data Sources | Weather Forecasting & Climate
Frequently asked questions
Average temperature in December
Simi Valley, CA
- Average high temperature in December: 60.1°F
The warmest month (with the highest average high temperature) is August (82.2°F).
The month with the lowest average high temperature is December (60.1°F).
- Average low temperature in December: 46.4°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 (46.4°F).
Average pressure in December
Simi Valley, CA
- Average pressure in December: 30.08"Hg
The month with the highest atmospheric pressure is January (30.11"Hg).
The months with the lowest atmospheric pressure are June and September (29.9"Hg).
Average wind speed in December
Simi Valley, CA
- Average wind speed in December: 6.5mph
The windiest month (with the highest average wind speed) is December (6.5mph).
The calmest month (with the lowest average wind speed) is August (4.3mph).
Average humidity in December
Simi Valley, CA
- Average humidity in December: 55%
The month with the highest relative humidity is June (62%).
The month with the lowest relative humidity is November (50%).
Average rainfall in December
Simi Valley, CA
- Average rainfall in December: 1.69"
The wettest month (with the highest rainfall) is February (1.93").
The driest month (with the least rainfall) is June (0.08").
Average rainfall days in December
Simi Valley, CA
- Average rainfall days in December: 6.4 days
The month with the highest number of rainy days is March (8 days).
The months with the least rainy days are June and August (1.5 days).
Average daylight in December /
Average sunshine in December
Simi Valley, CA
- Average daylight in December: 9h and 54min
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 December: 6h and 48min
The months with the most sunshine are June and July (Average sunshine: 12h and 6min).
The months with the least sunshine are January, February and December (Average sunshine: 6h and 48min).
Average sunshine days in December
Simi Valley, CA
- Average sunshine days in December: 23.2 days
The month with the most sunshine days is August (25.4 days).
The month with the least sunshine days is February (20.9 days).
Average UV index in December
Simi Valley, CA
- Average UV index in December: 3
The months with the highest UV index are June, July and August (UV index 6).
The month with the lowest UV index is December (UV index 3).
Average cloud cover in December
Simi Valley, CA
- Average cloud cover in December: 22
The month with the most cloud cover is March (Cloud cover 23).
The month with the least cloud cover is August (Cloud cover 5).
Average visibility in December
Simi Valley, CA
- Average visibility in December: 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).
