Average Weather in December in Spiro Oklahoma, United States
Daily high temperatures decrease by 7°F, from 57°F to 51°F, rarely falling below 35°F or exceeding 71°F.
Daily low temperatures decrease by 6°F, from 38°F to 31°F, rarely falling below 18°F or exceeding 51°F.
For reference, on July 25, the hottest day of the year, temperatures in Spiro typically range from 72°F to 94°F, while on January 7, the coldest day of the year, they range from 31°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 Spiro experiences essentially constant cloud cover, with the percentage of time that the sky is overcast or mostly cloudy remaining about 45% throughout the month. The highest chance of overcast or mostly cloudy conditions is 47% on December 27.
The clearest day of the month is December 3, with clear, mostly clear, or partly cloudy conditions 57% of the time.
For reference, on February 17, the cloudiest day of the year, the chance of overcast or mostly cloudy conditions is 48%, while on October 5, the clearest day of the year, the chance of clear, mostly clear, or partly cloudy skies is 72%.
Cloud Cover Categories in December
A wet day is one with at least 0.04 inches of liquid or liquid-equivalent precipitation. In Spiro, the chance of a wet day over the course of December is decreasing, starting the month at 24% and ending it at 19%.
For reference, the year's highest daily chance of a wet day is 44% on May 21, and its lowest chance is 18% on January 12.
Over the course of December in Spiro, the chance of a day with only rain decreases from 22% to 16%, 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 1% throughout.
Probability of Precipitation in December
The average sliding 31-day rainfall during December in Spiro is rapidly decreasing, starting the month at 3.7 inches, when it rarely exceeds 7.4 inches or falls below 0.7 inches, and ending the month at 2.6 inches, when it rarely exceeds 6.0 inches or falls below 0.5 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 Spiro is essentially constant, remaining about 0.1 inches throughout, and rarely exceeding 0.4 inches or falling to 0.0 inches.
Average Monthly Liquid-Equivalent Snowfall in December
Over the course of December in Spiro, the length of the day is essentially constant. The shortest day of the month is December 21, with 9 hours, 47 minutes of daylight and the longest day is December 1, with 9 hours, 58 minutes of daylight.
Hours of Daylight and Twilight in December
The earliest sunrise of the month in Spiro is 7:08 AM on December 1 and the latest sunrise is 18 minutes later at 7:26 AM on December 31.
The earliest sunset is 5:05 PM on December 5 and the latest sunset is 10 minutes later at 5:16 PM on December 31.
Daylight saving time is observed in Spiro 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 6:04 AM and sets 14 hours, 32 minutes later, at 8:36 PM, while on December 21, the shortest day of the year, it rises at 7:23 AM and sets 9 hours, 47 minutes later, at 5:10 PM.
Sunrise & Sunset with Twilight and Daylight Saving Time in December
The chance that a given day will be muggy in Spiro is essentially constant during December, remaining around 0% throughout.
For reference, on July 22, the muggiest day of the year, there are muggy conditions 87% of the time, while on January 12, 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 Spiro is essentially constant during December, remaining within 0.1 miles per hour of 6.4 miles per hour throughout.
For reference, on March 23, the windiest day of the year, the daily average wind speed is 7.5 miles per hour, while on August 3, the calmest day of the year, the daily average wind speed is 4.6 miles per hour.
Average Wind Speed in December
Wind Direction in December
The growing season in Spiro typically lasts for 7.5 months (229 days), from around March 24 to around November 8, rarely starting before March 1 or after April 16, and rarely ending before October 19 or after November 29.
The month of December in Spiro is very likely fully outside of the growing season, with the chance that a given day is in the growing season reaching a low of -0% on December 28.
Time Spent in Various Temperature Bands and the Growing Season in December
The average accumulated growing degree days in Spiro are gradually increasing during December, increasing by 58°F, from 5,209°F to 5,267°F, over the course of the month.
Growing Degree Days in December
The average daily incident shortwave solar energy in Spiro is essentially constant during December, remaining within 0.1 kWh of 2.6 kWh throughout.
The lowest average daily incident shortwave solar energy during December is 2.5 kWh on December 23.
Average Daily Incident Shortwave Solar Energy in December
For the purposes of this report, the geographical coordinates of Spiro are 35.241 deg latitude, -94.620 deg longitude, and 459 ft elevation.
The topography within 2 miles of Spiro contains only modest variations in elevation, with a maximum elevation change of 200 feet and an average elevation above sea level of 479 feet. Within 10 miles contains only modest variations in elevation (558 feet). Within 50 miles contains significant variations in elevation (2,349 feet).
The area within 2 miles of Spiro is covered by cropland (81%) and artificial surfaces (10%), within 10 miles by cropland (84%) and trees (11%), and within 50 miles by trees (58%) and cropland (36%).
This report illustrates the typical weather in Spiro 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 Spiro.
For each station, the records are corrected for the elevation difference between that station and Spiro 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 Spiro is computed as the weighted average of the individual contributions from each station, with weights proportional to the inverse of the distance between Spiro and a given station.
The stations contributing to this reconstruction are: Robert S Kerr Airport (36%, 25 kilometers, south); Fort Smith Municipal Airport (34%, 25 kilometers, northeast); and Sallisaw Municipal Airport (30%, 27 kilometers, northwest).
Time zones for aiports and weather stations are provided by AskGeo.com .