Average Weather in December in St. Day United Kingdom
Daily high temperatures decrease by 2°F, from 50°F to 48°F, rarely falling below 41°F or exceeding 55°F.
Daily low temperatures are around 42°F, rarely falling below 32°F or exceeding 51°F.
For reference, on August 2, the hottest day of the year, temperatures in St. Day typically range from 57°F to 65°F, while on February 18, the coldest day of the year, they range from 40°F to 47°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 St. Day experiences essentially constant cloud cover, with the percentage of time that the sky is overcast or mostly cloudy remaining about 63% throughout the month. The highest chance of overcast or mostly cloudy conditions is 65% on December 26.
The clearest day of the month is December 3, with clear, mostly clear, or partly cloudy conditions 39% of the time.
For reference, on December 25, the cloudiest day of the year, the chance of overcast or mostly cloudy conditions is 65%, while on July 24, the clearest day of the year, the chance of clear, mostly clear, or partly cloudy skies is 56%.
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 St. Day, the chance of a wet day over the course of December is gradually increasing, starting the month at 41% and ending it at 45%.
For reference, the year's highest daily chance of a wet day is 45% on January 6, and its lowest chance is 22% on July 24.
Probability of Precipitation in December
To show variation within the month and not just the monthly total, we show the rainfall accumulated over a sliding 31-day period centered around each day.
The average sliding 31-day rainfall during December in St. Day is gradually increasing, starting the month at 3.4 inches, when it rarely exceeds 5.5 inches or falls below 1.6 inches, and ending the month at 3.7 inches, when it rarely exceeds 6.4 inches or falls below 1.3 inches.
Average Monthly Rainfall in December
Over the course of December in St. Day, the length of the day is essentially constant. The shortest day of the month is December 21, with 8 hours, 2 minutes of daylight and the longest day is December 1, with 8 hours, 22 minutes of daylight.
Hours of Daylight and Twilight in December
The earliest sunrise of the month in St. Day is 7:58 AM on December 1 and the latest sunrise is 22 minutes later at 8:20 AM on December 31.
The earliest sunset is 4:17 PM on December 12 and the latest sunset is 10 minutes later at 4:27 PM on December 31.
Daylight saving time is observed in St. Day during 2021, 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 5:10 AM and sets 16 hours, 25 minutes later, at 9:34 PM, while on December 21, the shortest day of the year, it rises at 8:17 AM and sets 8 hours, 2 minutes later, at 4:19 PM.
Sunrise & Sunset with Twilight in December
The figure below presents a compact representation of key lunar data for December 2021. The horizontal axis is the day, the vertical axis is the hour of the day, and the colored areas indicate when the moon is above the horizon. The vertical gray bars (new Moons) and blue bars (full Moons) indicate key Moon phases. The label associated with each bar indicates the date and time that the phase is obtained, and the companion time labels indicate the rise and set times of the Moon for the nearest time interval in which the moon is above the horizon.
Moon Rise, Set & Phases in December
We base the humidity comfort level on the dew point, as it determines whether perspiration will evaporate from the skin, thereby cooling the body. Lower dew points feel drier and higher dew points feel more humid. Unlike temperature, which typically varies significantly between night and day, dew point tends to change more slowly, so while the temperature may drop at night, a muggy day is typically followed by a muggy night.
The chance that a given day will be muggy in St. Day is essentially constant during December, remaining around 0% throughout.
For reference, on August 9, the muggiest day of the year, there are muggy conditions 1% 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
This section discusses the wide-area hourly average wind vector (speed and direction) at 10 meters above the ground. The wind experienced at any given location is highly dependent on local topography and other factors, and instantaneous wind speed and direction vary more widely than hourly averages.
The average hourly wind speed in St. Day is increasing during December, increasing from 19.4 miles per hour to 20.5 miles per hour over the course of the month.
For reference, on January 1, the windiest day of the year, the daily average wind speed is 20.6 miles per hour, while on August 3, the calmest day of the year, the daily average wind speed is 13.2 miles per hour.
Average Wind Speed in December
The hourly average wind direction in St. Day throughout December is predominantly from the west, with a peak proportion of 40% on December 31.
Wind Direction in December
St. Day 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 St. Day is gradually decreasing during December, falling by 2°F, from 54°F to 51°F, over the course of the month.
Average Water Temperature in December
Definitions of the growing season vary throughout the world, but for the purposes of this report, we define it as the longest continuous period of non-freezing temperatures (≥ 32°F) in the year (the calendar year in the Northern Hemisphere, or from July 1 until June 30 in the Southern Hemisphere).
The growing season in St. Day typically lasts for 9.8 months (295 days), from around February 27 to around December 19, rarely starting after April 1, or ending before November 20.
During December in St. Day, the chance that a given day is within the growing season is rapidly decreasing falling from 76% to 31% over the course of the month.
Time Spent in Various Temperature Bands and the Growing Season in December
Growing degree days are a measure of yearly heat accumulation used to predict plant and animal development, and defined as the integral of warmth above a base temperature, discarding any excess above a maximum temperature. In this report, we use a base of 50°F and a cap of 86°F.
The average accumulated growing degree days in St. Day are essentially constant during December, remaining within 9°F of 1,424°F throughout.
Growing Degree Days in December
This section discusses the total daily incident shortwave solar energy reaching the surface of the ground over a wide area, taking full account of seasonal variations in the length of the day, the elevation of the Sun above the horizon, and absorption by clouds and other atmospheric constituents. Shortwave radiation includes visible light and ultraviolet radiation.
The average daily incident shortwave solar energy in St. Day is essentially constant during December, remaining within 0.1 kWh of 0.8 kWh throughout.
The lowest average daily incident shortwave solar energy during December is 0.7 kWh on December 25.
Average Daily Incident Shortwave Solar Energy in December
For the purposes of this report, the geographical coordinates of St. Day are 50.240 deg latitude, -5.186 deg longitude, and 417 ft elevation.
The topography within 2 miles of St. Day contains significant variations in elevation, with a maximum elevation change of 663 feet and an average elevation above sea level of 368 feet. Within 10 miles contains significant variations in elevation (827 feet). Within 50 miles also contains very significant variations in elevation (1,319 feet).
The area within 2 miles of St. Day is covered by grassland (53%), cropland (30%), and artificial surfaces (14%), within 10 miles by cropland (47%) and water (24%), and within 50 miles by water (82%).
This report illustrates the typical weather in St. Day, 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 2 weather stations near enough to contribute to our estimation of the temperature and dew point in St. Day.
For each station, the records are corrected for the elevation difference between that station and St. Day 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 St. Day is computed as the weighted average of the individual contributions from each station, with weights proportional to the inverse of the distance between St. Day and a given station.
All data relating to the Sun's position (e.g., sunrise and sunset) are computed using astronomical formulas from the book, Astronomical Algorithms 2nd Edition , by Jean Meeus.
All other weather data, including cloud cover, precipitation, wind speed and direction, and solar flux, come from NASA's MERRA-2 Modern-Era Retrospective Analysis . This reanalysis combines a variety of wide-area measurements in a state-of-the-art global meteorological model to reconstruct the hourly history of weather throughout the world on a 50-kilometer grid.
Land Use data comes from the Global Land Cover SHARE database , published by the Food and Agriculture Organization of the United Nations.
Elevation data comes from the Shuttle Radar Topography Mission (SRTM) , published by NASA's Jet Propulsion Laboratory.
Names, locations, and time zones of places and some airports come from the GeoNames Geographical Database .
Time zones for airports and weather stations are provided by AskGeo.com .
Maps are © Esri, with data from National Geographic, Esri, DeLorme, NAVTEQ, UNEP-WCMC, USGS, NASA, ESA, METI, NRCAN, GEBCO, NOAA, and iPC.
The information on this site is provided as is, without any assurances as to its accuracy or suitability for any purpose. Weather data is prone to errors, outages, and other defects. We assume no responsibility for any decisions made on the basis of the content presented on this site.
We draw particular cautious attention to our reliance on the MERRA-2 model-based reconstructions for a number of important data series. While having the tremendous advantages of temporal and spatial completeness, these reconstructions: (1) are based on computer models that may have model-based errors, (2) are coarsely sampled on a 50 km grid and are therefore unable to reconstruct the local variations of many microclimates, and (3) have particular difficulty with the weather in some coastal areas, especially small islands.
We further caution that our travel scores are only as good as the data that underpin them, that weather conditions at any given location and time are unpredictable and variable, and that the definition of the scores reflects a particular set of preferences that may not agree with those of any particular reader.