December weather forecastGrand Terrace, CA
December
Weather in December
The first month of the winter, December, is still a mild month in Grand Terrace, California, with an average temperature fluctuating between 43.7°F (6.5°C) and 59.9°F (15.5°C).Temperature
Grand Terrace's December weather reaches an average high of 59.9°F (15.5°C) and an average low of 43.7°F (6.5°C), making it the coldest month.Humidity
The average relative humidity in December is 51%.Rainfall
The month with the most rainfall is December, when the rain falls for 6 days and typically aggregates up to 1.42" (36mm) of precipitation.Snowfall
In Grand Terrace, snow does not fall in January, March through December.Daylight
The month with the shortest days is December, with an average of 9h and 54min of daylight.On the first day of the month, sunrise is at 6:37 am and sunset at 4:39 pm. On the last day of December, sunrise is at 6:54 am and sunset at 4:50 pm PST.
Sunshine
The month with the least sunshine is December, with an average of 6.9h of sunshine.UV index
December is the month with the lowest UV index in Grand Terrace, with an average maximum UV index of 3. A UV Index of 3 to 5 symbolizes a medium vulnerability from exposure to the Sun's UV radiation for ordinary individuals.Note: The maximum daily UV index of 3 during December translates into the following directions:
Prioritize safety - Recommendations to avert sunburn are shared. UV radiation is strongest from the Sun during midday; protect yourself by staying in shaded areas. Sun protection is enhanced with clothing that boasts a tight weave yet offers a loose fit.
Published by: Weather U.S. | About Us
Data Sources | Weather Forecasting & Climate
Frequently asked questions
Average temperature in December
Grand Terrace, CA
- Average high temperature in December: 59.9°F
The warmest month (with the highest average high temperature) is August (91.9°F).
The month with the lowest average high temperature is December (59.9°F).
- Average low temperature in December: 43.7°F
The month with the highest average low temperature is August (65.8°F).
The coldest month (with the lowest average low temperature) is February (43.5°F).
Average pressure in December
Grand Terrace, CA
- Average pressure in December: 30.07"Hg
The month with the highest atmospheric pressure is January (30.1"Hg).
The month with the lowest atmospheric pressure is June (29.85"Hg).
Average wind speed in December
Grand Terrace, CA
- Average wind speed in December: 5.2mph
The windiest months (with the highest average wind speed) are April and May (6mph).
The calmest month (with the lowest average wind speed) is September (4.5mph).
Average humidity in December
Grand Terrace, CA
- Average humidity in December: 51%
The month with the highest relative humidity is February (53%).
The month with the lowest relative humidity is August (38%).
Average rainfall in December
Grand Terrace, CA
- Average rainfall in December: 1.42"
The wettest month (with the highest rainfall) is December (1.42").
The driest month (with the least rainfall) is June (0.04").
Average rainfall days in December
Grand Terrace, CA
- Average rainfall days in December: 6 days
The month with the highest number of rainy days is March (6.7 days).
The month with the least rainy days is June (1.2 days).
Average snowfall days in December
Grand Terrace, CA
- Average snowfall days in December: 0 days
The month with the highest number of snowfall days is February (0.1 days).
The months with the least snowfall days are January, March, April, May, June, July, August, September, October, November and December (0 days).
Average daylight in December /
Average sunshine in December
Grand Terrace, 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 54min
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 54min).
Average sunshine days in December
Grand Terrace, CA
- Average sunshine days in December: 24.3 days
The months with the most sunshine days are June and October (27.9 days).
The month with the least sunshine days is February (21.7 days).
Average UV index in December
Grand Terrace, CA
- Average UV index in December: 3
The months with the highest UV index are June, July and August (UV index 7).
The month with the lowest UV index is December (UV index 3).
Average cloud cover in December
Grand Terrace, CA
- Average cloud cover in December: 21
The months with the most cloud cover are February and December (Cloud cover 21).
The month with the least cloud cover is August (Cloud cover 5).
Average visibility in December
Grand Terrace, 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).
