December weather forecastSunnyvale, TX
December
Weather in December
December, the first month of the winter in Sunnyvale, is still a mild month, with an average temperature fluctuating between 55.8°F (13.2°C) and 41.7°F (5.4°C).Temperature
December's arrival signals a moderate reduction in the average high-temperature, easing from an enjoyable 64°F (17.8°C) in November to a mild 55.8°F (13.2°C). The temperature dips to an average of 41.7°F (5.4°C) during December nights.Humidity
The average relative humidity in December is 70%.Rainfall
In Sunnyvale, in December, during 10.2 rainfall days, 2.28" (58mm) of precipitation is typically accumulated. Throughout the year, there are 149.6 rainfall days, and 33.35" (847mm) of precipitation is accumulated.Snowfall
March through December are months without snowfall in Sunnyvale.Daylight
The month with the shortest days is December, with an average of 10h and 0min of daylight.On the first day of December, sunrise is at 7:11 am and sunset at 5:19 pm. On the last day of the month, sunrise is at 7:28 am and sunset at 5:30 pm CST.
Sunshine
The month with the least sunshine is December, with an average of 5.5h of sunshine.UV index
The months with the lowest UV index are January and December, with an average maximum UV index of 3. A UV Index of 3 to 5 symbolizes a moderate health risk from exposure to the Sun's UV rays for ordinary individuals.Note: In December, the maximum UV index of 3 suggests these recommendations:
Act with care - The need to guard against sun damage is communicated. Avoiding direct sunlight during midday hours helps reduce the risk from intense UV radiation. Enhance your sun protection with tightly woven, yet airy clothing. Remember! The Sun's UV radiation can be magnified almost twofold by the reflection of snow.
Published by: Weather U.S. | About Us
Data Sources | Weather Forecasting & Climate
Frequently asked questions
Average temperature in December
Sunnyvale, TX
- Average high temperature in December: 55.8°F
The warmest month (with the highest average high temperature) is August (95.5°F).
The month with the lowest average high temperature is January (54.3°F).
- Average low temperature in December: 41.7°F
The months with the highest average low temperature are July and August (75.7°F).
The coldest month (with the lowest average low temperature) is January (38.8°F).
Average pressure in December
Sunnyvale, TX
- Average pressure in December: 30.13"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 December
Sunnyvale, TX
- Average wind speed in December: 8.4mph
The windiest month (with the highest average wind speed) is March (9.8mph).
The calmest month (with the lowest average wind speed) is September (6.6mph).
Average humidity in December
Sunnyvale, TX
- Average humidity in December: 70%
The month with the highest relative humidity is May (75%).
The month with the lowest relative humidity is August (58%).
Average rainfall in December
Sunnyvale, TX
- Average rainfall in December: 2.28"
The wettest month (with the highest rainfall) is October (4.29").
The driest month (with the least rainfall) is February (1.85").
Average rainfall days in December
Sunnyvale, TX
- Average rainfall days in December: 10.2 days
The month with the highest number of rainy days is May (15.4 days).
The month with the least rainy days is January (7.6 days).
Average snowfall in December
Sunnyvale, TX
- Average snowfall in December: 0"
The month with the highest snowfall is February (0.67").
The months with the least snowfall are March, April, May, June, July, August, September, October, November and December (0").
Average snowfall days in December
Sunnyvale, TX
- Average snowfall days in December: 0.2 days
The month with the highest number of snowfall days is February (1.2 days).
The months with the least snowfall days are April, May, June, July, August, September, October and November (0 days).
Average daylight in December /
Average sunshine in December
Sunnyvale, TX
- Average daylight in December: 10h and 0min
The month with the longest days is June (Average daylight: 14h and 18min).
The month with the shortest days is December (Average daylight: 10h and 0min).
- Average sunshine in December: 5h and 30min
The month with the most sunshine is August (Average sunshine: 11h and 6min).
The month with the least sunshine is December (Average sunshine: 5h and 30min).
Average sunshine days in December
Sunnyvale, TX
- Average sunshine days in December: 19 days
The month with the most sunshine days is January (21.8 days).
The month with the least sunshine days is September (13 days).
Average UV index in December
Sunnyvale, TX
- Average UV index in December: 3
The months with the highest UV index are June, July and August (UV index 7).
The months with the lowest UV index are January and December (UV index 3).
Average cloud cover in December
Sunnyvale, TX
- Average cloud cover in December: 38
The month with the most cloud cover is February (Cloud cover 42).
The month with the least cloud cover is August (Cloud cover 20).
Average visibility in December
Sunnyvale, TX
- 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).
