Average Weather in December in Twain Harte California, United States
In Twain Harte, the month of December is characterized by gradually falling daily high temperatures, with daily highs decreasing by 4°F, from 51°F to 48°F over the course of the month, and rarely exceeding 60°F or dropping below 39°F. The lowest daily average high temperature is 47°F on December 27.
Daily low temperatures decrease by 3°F, from 34°F to 31°F, rarely falling below 22°F or exceeding 42°F. The lowest daily average low temperature is 31°F on December 23.
For reference, on July 28, the hottest day of the year, temperatures in Twain Harte typically range from 56°F to 85°F, while on December 23, the coldest day of the year, they range from 31°F to 48°F.
Average High and Low Temperature in December
The figure below shows you a compact characterization of the hourly average temperatures for the quarter of the year centered on December. The horizontal axis is the day, the vertical axis is the hour of the day, and the color is the average temperature for that hour and day.
Average Hourly Temperature in December
The month of December in Twain Harte experiences essentially constant cloud cover, with the percentage of time that the sky is overcast or mostly cloudy remaining about 52% throughout the month. The highest chance of overcast or mostly cloudy conditions is 54% on December 28.
The clearest day of the month is December 1, with clear, mostly clear, or partly cloudy conditions 50% of the time.
For reference, on February 21, the cloudiest day of the year, the chance of overcast or mostly cloudy conditions is 56%, while on August 8, the clearest day of the year, the chance of clear, mostly clear, or partly cloudy skies is 90%.
Cloud Cover Categories in December
A wet day is one with at least 0.04 inches of liquid or liquid-equivalent precipitation. In Twain Harte, the chance of a wet day over the course of December is essentially constant, remaining around 27% throughout.
For reference, the year's highest daily chance of a wet day is 32% on February 21, and its lowest chance is 0% on August 6.
Over the course of December in Twain Harte, the chance of a day with only rain remains an essentially constant 22% throughout, the chance of a day with mixed snow and rain increases from 2% to 5%, and the chance of a day with only snow remains an essentially constant 1% throughout.
Probability of Precipitation in December
The average sliding 31-day rainfall during December in Twain Harte is increasing, starting the month at 3.3 inches, when it rarely exceeds 7.1 inches or falls below 0.5 inches, and ending the month at 4.1 inches, when it rarely exceeds 9.2 inches or falls below 0.2 inches.
Average Monthly Rainfall in December
We report snowfall in liquid-equivalent terms. The actual depth of new snowfall is typically between 5 and 10 times the liquid-equivalent amount, assuming the ground is frozen. As with rainfall, we consider the liquid-equivalent snowfall accumulated over a sliding 31-day period centered around each day.
The average sliding 31-day liquid-equivalent snowfall during December in Twain Harte is essentially constant, remaining about 0.2 inches throughout, and rarely exceeding 0.6 inches or falling below -0.0 inches.
The highest average 31-day liquid-equivalent accumulation is 0.2 inches on December 25.
Average Monthly Liquid-Equivalent Snowfall in December
Over the course of December in Twain Harte, the length of the day is essentially constant. The shortest day of the month is December 21, with 9 hours, 31 minutes of daylight and the longest day is December 1, with 9 hours, 43 minutes of daylight.
Hours of Daylight and Twilight in December
The earliest sunrise of the month in Twain Harte is 6:58 AM on December 1 and the latest sunrise is 18 minutes later at 7:16 AM on December 31.
The earliest sunset is 4:41 PM on December 6 and the latest sunset is 10 minutes later at 4:51 PM on December 31.
Daylight saving time is observed in Twain Harte during 2017, but it neither starts nor ends during December, so the entire month is in standard time.
For reference, on June 21, the longest day of the year, the Sun rises at 5:38 AM and sets 14 hours, 49 minutes later, at 8:27 PM, while on December 21, the shortest day of the year, it rises at 7:13 AM and sets 9 hours, 31 minutes later, at 4:44 PM.
Sunrise & Sunset with Twilight and Daylight Saving Time in December
The chance that a given day will be muggy in Twain Harte is essentially constant during December, remaining around 0% throughout.
Humidity Comfort Levels in December
The average hourly wind speed in Twain Harte is essentially constant during December, remaining within 0.1 miles per hour of 5.5 miles per hour throughout.
For reference, on February 4, the windiest day of the year, the daily average wind speed is 5.6 miles per hour, while on September 24, the calmest day of the year, the daily average wind speed is 5.0 miles per hour.
The highest daily average wind speed during December is 5.6 miles per hour on December 23.
Average Wind Speed in December
Wind Direction in December
The growing season in Twain Harte typically lasts for 6.4 months (195 days), from around April 20 to around November 1, rarely starting before March 26 or after May 13, and rarely ending before October 9 or after November 24.
The month of December in Twain Harte is very likely fully outside of the growing season, with the chance that a given day is in the growing season gradually decreasing from 6% to 0% over the course of the month.
Time Spent in Various Temperature Bands and the Growing Season in December
The average accumulated growing degree days in Twain Harte is essentially constant during December, remaining within 4°F of 2,940°F throughout.
Growing Degree Days in December
The average daily incident shortwave solar energy in Twain Harte is essentially constant during December, remaining within 0.1 kWh of 2.4 kWh throughout.
The lowest average daily incident shortwave solar energy during December is 2.3 kWh on December 23.
Average Daily Incident Shortwave Solar Energy in December
For the purposes of this report, the geographical coordinates of Twain Harte are 38.040 deg latitude, -120.233 deg longitude, and 3,727 ft elevation.
The topography within 2 miles of Twain Harte contains very significant variations in elevation, with a maximum elevation change of 1,785 feet and an average elevation above sea level of 3,811 feet. Within 10 miles contains very significant variations in elevation (5,118 feet). Within 50 miles also contains extreme variations in elevation (12,208 feet).
The area within 2 miles of Twain Harte is covered by trees (51%) and shrubs (49%), within 10 miles by trees (48%) and shrubs (47%), and within 50 miles by shrubs (31%) and trees (31%).
This report illustrates the typical weather in Twain Harte year round, based on a statistical analysis of historical hourly weather reports and model reconstructions from January 1, 1980 to December 31, 2016.
Temperature and Dew Point
There are 5 weather stations near enough to contribute to our estimation of the temperature and dew point in Twain Harte.
For each station, the records are corrected for the elevation difference between that station and Twain Harte according to the International Standard Atmosphere , and by the relative change present in the MERRA-2 satellite-era reanalysis between the two locations.
The estimated value at Twain Harte is computed as the weighted average of the individual contributions from each station, with weights proportional to the inverse of the distance between Twain Harte and a given station.
The stations contributing to this reconstruction are: Bridgeport Sonora Junction (21%, 72 kilometers, northeast); Modesto City-County Airport (16%, 78 kilometers, southwest); Castle Airport (17%, 79 kilometers, south); Placerville Airport (28%, 88 kilometers, northwest); and Lake Tahoe Airport (18%, 98 kilometers, north).
Time zones for aiports and weather stations are provided by AskGeo.com .