Average Weather in December in Seymour Connecticut, United States
Daily high temperatures decrease by 8°F, from 45°F to 37°F, rarely falling below 26°F or exceeding 57°F.
Daily low temperatures decrease by 7°F, from 32°F to 25°F, rarely falling below 12°F or exceeding 43°F.
For reference, on July 21, the hottest day of the year, temperatures in Seymour typically range from 65°F to 81°F, while on January 29, the coldest day of the year, they range from 21°F to 35°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 Seymour experiences essentially constant cloud cover, with the percentage of time that the sky is overcast or mostly cloudy remaining about 51% throughout the month.
The clearest day of the month is December 3, with clear, mostly clear, or partly cloudy conditions 51% of the time.
For reference, on February 25, the cloudiest day of the year, the chance of overcast or mostly cloudy conditions is 53%, while on September 6, the clearest day of the year, the chance of clear, mostly clear, or partly cloudy skies is 65%.
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 Seymour, 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 36% on May 31, and its lowest chance is 23% on January 29.
Over the course of December in Seymour, the chance of a day with only rain decreases from 21% to 14%, 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 increases from 2% to 8%.
Probability of Precipitation in December
The average sliding 31-day rainfall during December in Seymour is rapidly decreasing, starting the month at 3.4 inches, when it rarely exceeds 5.8 inches or falls below 1.4 inches, and ending the month at 2.2 inches, when it rarely exceeds 3.9 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 Seymour is gradually increasing, starting the month at 0.4 inches, when it rarely exceeds 1.0 inches, and ending the month at 0.9 inches, when it rarely exceeds 1.9 inches or falls below 0.1 inches.
Average Monthly Liquid-Equivalent Snowfall in December
Over the course of December in Seymour, the length of the day is essentially constant. The shortest day of the month is December 21, with 9 hours, 11 minutes of daylight and the longest day is December 1, with 9 hours, 25 minutes of daylight.
Hours of Daylight and Twilight in December
The earliest sunrise of the month in Seymour is 6:58 AM on December 1 and the latest sunrise is 19 minutes later at 7:18 AM on December 31.
The earliest sunset is 4:22 PM on December 8 and the latest sunset is 10 minutes later at 4:32 PM on December 31.
Daylight saving time is observed in Seymour 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 5:18 AM and sets 15 hours, 10 minutes later, at 8:29 PM, while on December 21, the shortest day of the year, it rises at 7:15 AM and sets 9 hours, 11 minutes later, at 4:25 PM.
Sunrise & Sunset with Twilight and Daylight Saving Time in December
The chance that a given day will be muggy in Seymour is essentially constant during December, remaining around 0% throughout.
For reference, on July 30, the muggiest day of the year, there are muggy conditions 44% 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 Seymour is gradually increasing during December, increasing from 6.7 miles per hour to 7.3 miles per hour over the course of the month.
For reference, on February 26, the windiest day of the year, the daily average wind speed is 7.8 miles per hour, while on August 1, the calmest day of the year, the daily average wind speed is 4.3 miles per hour.
Average Wind Speed in December
Wind Direction in December
Seymour 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 Seymour is rapidly decreasing during December, falling by 7°F, from 50°F to 43°F, over the course of the month.
Average Water Temperature in December
The growing season in Seymour typically lasts for 6.2 months (189 days), from around April 15 to around October 21, rarely starting before March 30 or after May 3, and rarely ending before October 4 or after November 8.
The month of December in Seymour 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 Seymour are essentially constant during December, remaining within 4°F of 2,841°F throughout.
Growing Degree Days in December
The average daily incident shortwave solar energy in Seymour is essentially constant during December, remaining within 0.1 kWh of 1.8 kWh throughout.
The lowest average daily incident shortwave solar energy during December is 1.7 kWh on December 23.
Average Daily Incident Shortwave Solar Energy in December
For the purposes of this report, the geographical coordinates of Seymour are 41.397 deg latitude, -73.076 deg longitude, and 400 ft elevation.
The topography within 2 miles of Seymour contains significant variations in elevation, with a maximum elevation change of 591 feet and an average elevation above sea level of 324 feet. Within 10 miles contains significant variations in elevation (948 feet). Within 50 miles contains very significant variations in elevation (2,365 feet).
The area within 2 miles of Seymour is covered by trees (60%) and artificial surfaces (40%), within 10 miles by trees (73%) and artificial surfaces (25%), and within 50 miles by trees (55%) and water (21%).
This report illustrates the typical weather in Seymour 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 Seymour.
For each station, the records are corrected for the elevation difference between that station and Seymour 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 Seymour is computed as the weighted average of the individual contributions from each station, with weights proportional to the inverse of the distance between Seymour and a given station.
The stations contributing to this reconstruction are: Waterbury-Oxford Airport (45%, 11 kilometers, northwest); Tweed-New Haven Airport (20%, 22 kilometers, southeast); Meriden Markham Municipal Airport (19%, 24 kilometers, northeast); and Igor I Sikorsky Memorial Airport (16%, 27 kilometers, south).
Time zones for aiports and weather stations are provided by AskGeo.com .