Average Weather in December in Grain Valley Missouri, United States
Daily high temperatures decrease by 8°F, from 48°F to 40°F, rarely falling below 23°F or exceeding 62°F.
Daily low temperatures decrease by 8°F, from 32°F to 24°F, rarely falling below 7°F or exceeding 45°F.
For reference, on July 21, the hottest day of the year, temperatures in Grain Valley typically range from 71°F to 89°F, while on January 22, the coldest day of the year, they range from 24°F to 40°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 Grain Valley experiences essentially constant cloud cover, with the percentage of time that the sky is overcast or mostly cloudy remaining about 49% throughout the month. The highest chance of overcast or mostly cloudy conditions is 50% on December 26.
The clearest day of the month is December 1, with clear, mostly clear, or partly cloudy conditions 53% of the time.
For reference, on February 12, the cloudiest day of the year, the chance of overcast or mostly cloudy conditions is 52%, while on August 26, the clearest day of the year, the chance of clear, mostly clear, or partly cloudy skies is 71%.
Cloud Cover Categories in December
A wet day is one with at least 0.04 inches of liquid or liquid-equivalent precipitation. In Grain Valley, the chance of a wet day over the course of December is gradually decreasing, starting the month at 16% and ending it at 13%.
For reference, the year's highest daily chance of a wet day is 44% on June 8, and its lowest chance is 11% on January 12.
Over the course of December in Grain Valley, the chance of a day with only rain decreases from 13% to 7%, the chance of a day with mixed snow and rain remains an essentially constant 2% throughout, and the chance of a day with only snow remains an essentially constant 3% throughout.
Probability of Precipitation in December
The average sliding 31-day rainfall during December in Grain Valley is decreasing, starting the month at 1.8 inches, when it rarely exceeds 3.8 inches or falls below 0.2 inches, and ending the month at 0.8 inches, when it rarely exceeds 1.9 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 Grain Valley is essentially constant, remaining about 0.2 inches throughout, and rarely exceeding 0.9 inches or falling to 0.0 inches.
Average Monthly Liquid-Equivalent Snowfall in December
Over the course of December in Grain Valley, the length of the day is essentially constant. The shortest day of the month is December 21, with 9 hours, 26 minutes of daylight and the longest day is December 1, with 9 hours, 38 minutes of daylight.
Hours of Daylight and Twilight in December
The earliest sunrise of the month in Grain Valley is 7:16 AM on December 1 and the latest sunrise is 19 minutes later at 7:35 AM on December 31.
The earliest sunset is 4:54 PM on December 7 and the latest sunset is 10 minutes later at 5:04 PM on December 31.
Daylight saving time is observed in Grain Valley during 2018, 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 5:51 AM and sets 14 hours, 55 minutes later, at 8:45 PM, while on December 21, the shortest day of the year, it rises at 7:32 AM and sets 9 hours, 26 minutes later, at 4:57 PM.
Sunrise & Sunset with Twilight and Daylight Saving Time in December
The chance that a given day will be muggy in Grain Valley is essentially constant during December, remaining around 0% throughout.
The lowest chance of a muggy day during December is 0% on December 17.
For reference, on July 23, the muggiest day of the year, there are muggy conditions 68% of the time, while on December 2, the least muggy day of the year, there are muggy conditions 0% of the time.
Humidity Comfort Levels in December
The average hourly wind speed in Grain Valley is essentially constant during December, remaining within 0.2 miles per hour of 10.8 miles per hour throughout.
For reference, on April 1, the windiest day of the year, the daily average wind speed is 12.4 miles per hour, while on August 7, the calmest day of the year, the daily average wind speed is 7.8 miles per hour.
The lowest daily average wind speed during December is 10.6 miles per hour on December 17.
Average Wind Speed in December
Wind Direction in December
The growing season in Grain Valley typically lasts for 6.8 months (209 days), from around April 4 to around October 30, rarely starting before March 14 or after April 22, and rarely ending before October 12 or after November 18.
The month of December in Grain Valley 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 Grain Valley are essentially constant during December, remaining within 9°F of 4,189°F throughout.
Growing Degree Days in December
The average daily incident shortwave solar energy in Grain Valley is essentially constant during December, remaining within 0.1 kWh of 2.2 kWh throughout.
The lowest average daily incident shortwave solar energy during December is 2.1 kWh on December 21.
Average Daily Incident Shortwave Solar Energy in December
For the purposes of this report, the geographical coordinates of Grain Valley are 39.015 deg latitude, -94.199 deg longitude, and 830 ft elevation.
The topography within 2 miles of Grain Valley contains only modest variations in elevation, with a maximum elevation change of 213 feet and an average elevation above sea level of 816 feet. Within 10 miles also contains only modest variations in elevation (387 feet). Within 50 miles contains only modest variations in elevation (535 feet).
The area within 2 miles of Grain Valley is covered by artificial surfaces (51%), cropland (31%), and trees (18%), within 10 miles by cropland (58%) and trees (24%), and within 50 miles by cropland (77%) and trees (12%).
This report illustrates the typical weather in Grain Valley 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 Grain Valley.
For each station, the records are corrected for the elevation difference between that station and Grain Valley 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 Grain Valley is computed as the weighted average of the individual contributions from each station, with weights proportional to the inverse of the distance between Grain Valley and a given station.
The stations contributing to this reconstruction are: Lee's Summit Municipal Airport (64%, 16 kilometers, west); Midwest National Air Center (20%, 37 kilometers, north); and Skyhaven Airport (16%, 43 kilometers, southeast).
Time zones for aiports and weather stations are provided by AskGeo.com .