Average Weather in December in Rupert Idaho, United States
Daily high temperatures decrease by 6°F, from 40°F to 34°F, rarely falling below 21°F or exceeding 52°F.
Daily low temperatures decrease by 4°F, from 24°F to 20°F, rarely falling below 5°F or exceeding 36°F. The lowest daily average low temperature is 20°F on December 29.
For reference, on July 26, the hottest day of the year, temperatures in Rupert typically range from 57°F to 88°F, while on December 29, the coldest day of the year, they range from 20°F to 34°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 Rupert experiences essentially constant cloud cover, with the percentage of time that the sky is overcast or mostly cloudy remaining about 53% throughout the month.
The clearest day of the month is December 9, with clear, mostly clear, or partly cloudy conditions 48% of the time.
For reference, on January 17, the cloudiest day of the year, the chance of overcast or mostly cloudy conditions is 55%, while on July 28, the clearest day of the year, the chance of clear, mostly clear, or partly cloudy skies is 82%.
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 Rupert, the chance of a wet day over the course of December is gradually decreasing, starting the month at 19% and ending it at 17%.
For reference, the year's highest daily chance of a wet day is 19% on December 6, and its lowest chance is 5% on July 4.
Over the course of December in Rupert, the chance of a day with only rain decreases from 12% 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 4% throughout.
Probability of Precipitation in December
The average sliding 31-day rainfall during December in Rupert is essentially constant, remaining about 0.8 inches throughout, and rarely exceeding 1.8 inches.
The highest average 31-day accumulation is 0.8 inches on December 6.
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 Rupert is essentially constant, remaining about 0.2 inches throughout, and rarely exceeding 0.8 inches or falling to 0.0 inches.
The highest average 31-day liquid-equivalent accumulation is 0.2 inches on December 18.
Average Monthly Liquid-Equivalent Snowfall in December
Over the course of December in Rupert, the length of the day is essentially constant. The shortest day of the month is December 21, with 9 hours, 3 minutes of daylight and the longest day is December 1, with 9 hours, 16 minutes of daylight.
Hours of Daylight and Twilight in December
The earliest sunrise of the month in Rupert is 7:45 AM on December 1 and the latest sunrise is 19 minutes later at 8:04 AM on December 31.
The earliest sunset is 5:01 PM on December 8 and the latest sunset is 10 minutes later at 5:11 PM on December 31.
Daylight saving time is observed in Rupert 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 5:56 AM and sets 15 hours, 19 minutes later, at 9:15 PM, while on December 21, the shortest day of the year, it rises at 8:01 AM and sets 9 hours, 3 minutes later, at 5:04 PM.
Sunrise & Sunset with Twilight in December
The chance that a given day will be muggy in Rupert is essentially constant during December, remaining around 0% throughout.
For reference, on July 24, 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 Rupert is essentially constant during December, remaining within 0.2 miles per hour of 8.4 miles per hour throughout.
For reference, on March 29, the windiest day of the year, the daily average wind speed is 9.6 miles per hour, while on August 3, the calmest day of the year, the daily average wind speed is 7.2 miles per hour.
The lowest daily average wind speed during December is 8.2 miles per hour on December 19.
Average Wind Speed in December
The hourly average wind direction in Rupert throughout December is predominantly from the west, with a peak proportion of 47% on December 1.
Wind Direction in December
The growing season in Rupert typically lasts for 4.9 months (151 days), from around May 5 to around October 3, rarely starting before April 18 or after May 25, and rarely ending before September 14 or after October 23.
The month of December in Rupert 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 Rupert are essentially constant during December, remaining within 1°F of 2,516°F throughout.
Growing Degree Days in December
The average daily incident shortwave solar energy in Rupert is essentially constant during December, remaining within 0.1 kWh of 1.9 kWh throughout.
The lowest average daily incident shortwave solar energy during December is 1.9 kWh on December 20.
Average Daily Incident Shortwave Solar Energy in December
For the purposes of this report, the geographical coordinates of Rupert are 42.619 deg latitude, -113.677 deg longitude, and 4,154 ft elevation.
The topography within 2 miles of Rupert is essentially flat, with a maximum elevation change of 10 feet and an average elevation above sea level of 4,155 feet. Within 10 miles is essentially flat (614 feet). Within 50 miles contains significant variations in elevation (7,343 feet).
The area within 2 miles of Rupert is covered by cropland (89%), within 10 miles by cropland (87%), and within 50 miles by shrubs (53%) and cropland (27%).
This report illustrates the typical weather in Rupert 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 3 weather stations near enough to contribute to our estimation of the temperature and dew point in Rupert.
For each station, the records are corrected for the elevation difference between that station and Rupert 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 Rupert is computed as the weighted average of the individual contributions from each station, with weights proportional to the inverse of the distance between Rupert and a given station.
The stations contributing to this reconstruction are: Burley Municipal Airport (94%, 11 kilometers, southwest); Pocatello Regional Airport (3.7%, 96 kilometers, east); and Malad City Airport (2.5%, 127 kilometers, east).
Time zones for aiports and weather stations are provided by AskGeo.com .