Average Weather in December in Idyllwild California, United States
Daily high temperatures decrease by 3°F, from 54°F to 51°F, rarely falling below 40°F or exceeding 64°F. The lowest daily average high temperature is 50°F on December 24.
Daily low temperatures decrease by 2°F, from 27°F to 25°F, rarely falling below 17°F or exceeding 35°F. The lowest daily average low temperature is 25°F on December 24.
For reference, on July 26, the hottest day of the year, temperatures in Idyllwild typically range from 54°F to 83°F, while on December 24, the coldest day of the year, they range from 25°F to 50°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 Idyllwild experiences essentially constant cloud cover, with the percentage of time that the sky is overcast or mostly cloudy remaining about 38% throughout the month. The highest chance of overcast or mostly cloudy conditions is 41% on December 27.
The clearest day of the month is December 1, with clear, mostly clear, or partly cloudy conditions 64% of the time.
For reference, on February 20, the cloudiest day of the year, the chance of overcast or mostly cloudy conditions is 45%, while on September 6, the clearest day of the year, the chance of clear, mostly clear, or partly cloudy skies is 89%.
Cloud Cover Categories in December
0% clear 20% mostly clear 40% partly cloudy 60% mostly cloudy 80% overcast 100%
A wet day is one with at least 0.04 inches of liquid or liquid-equivalent precipitation. In Idyllwild, the chance of a wet day over the course of December is gradually increasing, starting the month at 10% and ending it at 13%.
For reference, the year's highest daily chance of a wet day is 17% on February 21, and its lowest chance is 1% on June 17.
Over the course of December in Idyllwild, the chance of a day with only rain increases from 6% to 8%, the chance of a day with mixed snow and rain remains an essentially constant 4% throughout, 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 Idyllwild is gradually increasing, starting the month at 0.8 inches, when it rarely exceeds 2.0 inches, and ending the month at 1.2 inches, when it rarely exceeds 3.4 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 Idyllwild is essentially constant, remaining about 0.3 inches throughout, and rarely exceeding 1.4 inches or falling below -0.0 inches.
Average Monthly Liquid-Equivalent Snowfall in December
Over the course of December in Idyllwild, the length of the day is essentially constant. The shortest day of the month is December 20, with 9 hours, 55 minutes of daylight and the longest day is December 1, with 10 hours, 4 minutes of daylight.
Hours of Daylight and Twilight in December
The earliest sunrise of the month in Idyllwild is 6:34 AM on December 1 and the latest sunrise is 18 minutes later at 6:51 AM on December 31.
The earliest sunset is 4:38 PM on December 3 and the latest sunset is 11 minutes later at 4:48 PM on December 31.
Daylight saving time is observed in Idyllwild during 2020, but it neither starts nor ends during December, so the entire month is in standard time.
For reference, on June 20, the longest day of the year, the Sun rises at 5:36 AM and sets 14 hours, 24 minutes later, at 8:00 PM, while on December 21, the shortest day of the year, it rises at 6:47 AM and sets 9 hours, 55 minutes later, at 4:42 PM.
Sunrise & Sunset with Twilight in December
The chance that a given day will be muggy in Idyllwild is essentially constant during December, remaining around 0% throughout.
For reference, on August 15, the muggiest day of the year, there are muggy conditions 0% of the time, while on January 1, the least muggy day of the year, there are muggy conditions 0% of the time.
Humidity Comfort Levels in December
dry 55°F comfortable 60°F humid 65°F muggy 70°F oppressive 75°F miserable
The average hourly wind speed in Idyllwild is essentially constant during December, remaining within 0.1 miles per hour of 5.9 miles per hour throughout.
For reference, on April 25, the windiest day of the year, the daily average wind speed is 7.2 miles per hour, while on August 22, the calmest day of the year, the daily average wind speed is 5.2 miles per hour.
The highest daily average wind speed during December is 6.0 miles per hour on December 9.
Average Wind Speed in December
The wind direction in Idyllwild during December is predominantly out of the west from December 1 to December 5 and the north from December 5 to December 31.
Wind Direction in December
Idyllwild is located near a large body of water (e.g., ocean, sea, or large lake). This section reports on the wide-area average surface temperature of that water.
The average surface water temperature in Idyllwild is gradually decreasing during December, falling by 2°F, from 62°F to 60°F, over the course of the month.
Average Water Temperature in December
The growing season in Idyllwild typically lasts for 5.5 months (170 days), from around May 5 to around October 21, rarely starting before April 10 or after June 2, and rarely ending before September 29 or after November 12.
The month of December in Idyllwild is reliably fully outside of the growing season.
Time Spent in Various Temperature Bands and the Growing Season in December
The average accumulated growing degree days in Idyllwild are essentially constant during December, remaining within 11°F of 2,597°F throughout.
Growing Degree Days in December
The average daily incident shortwave solar energy in Idyllwild is essentially constant during December, remaining within 0.1 kWh of 3.2 kWh throughout.
The lowest average daily incident shortwave solar energy during December is 3.1 kWh on December 21.
Average Daily Incident Shortwave Solar Energy in December
For the purposes of this report, the geographical coordinates of Idyllwild are 33.740 deg latitude, -116.719 deg longitude, and 5,482 ft elevation.
The topography within 2 miles of Idyllwild contains large variations in elevation, with a maximum elevation change of 3,077 feet and an average elevation above sea level of 5,647 feet. Within 10 miles contains large variations in elevation (10,207 feet). Within 50 miles also contains extreme variations in elevation (11,719 feet).
The area within 2 miles of Idyllwild is covered by shrubs (78%) and trees (22%), within 10 miles by shrubs (75%) and trees (22%), and within 50 miles by shrubs (74%).
This report illustrates the typical weather in Idyllwild 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 4 weather stations near enough to contribute to our estimation of the temperature and dew point in Idyllwild.
For each station, the records are corrected for the elevation difference between that station and Idyllwild 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 Idyllwild is computed as the weighted average of the individual contributions from each station, with weights proportional to the inverse of the distance between Idyllwild and a given station.
The stations contributing to this reconstruction are: Palm Springs International Airport (24%, 22 kilometers, northeast); March Air Reserve Base (31%, 52 kilometers, west); Oceanside, Camp Pendleton, Marine Corps Air Station (19%, 76 kilometers, southwest); and Ramona Airport (26%, 80 kilometers, south).
Time zones for aiports and weather stations are provided by AskGeo.com .