Average Weather in December in Jacksonville Florida, United States
Daily low temperatures decrease by 5°F, from 52°F to 47°F, rarely falling below 33°F or exceeding 65°F.
For reference, on July 16, the hottest day of the year, temperatures in Jacksonville typically range from 75°F to 90°F, while on January 17, the coldest day of the year, they range from 46°F to 65°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
Kafr ad Dawwār, Egypt (6,277 miles away); Al Mindak, Saudi Arabia (7,294 miles); and Longmen, China (8,408 miles) are the far-away foreign places with temperatures most similar to Jacksonville (view comparison).
The month of December in Jacksonville experiences gradually increasing cloud cover, with the percentage of time that the sky is overcast or mostly cloudy increasing from 39% to 44%.
The clearest day of the month is December 5, with clear, mostly clear, or partly cloudy conditions 61% of the time.
For reference, on July 12, the cloudiest day of the year, the chance of overcast or mostly cloudy conditions is 62%, while on October 27, the clearest day of the year, the chance of clear, mostly clear, or partly cloudy skies is 66%.
Cloud Cover Categories in December
A wet day is one with at least 0.04 inches of liquid or liquid-equivalent precipitation. In Jacksonville, the chance of a wet day over the course of December is gradually increasing, starting the month at 20% and ending it at 22%.
For reference, the year's highest daily chance of a wet day is 59% on July 31, and its lowest chance is 17% on November 17.
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 Jacksonville is gradually increasing, starting the month at 2.1 inches, when it rarely exceeds 4.5 inches or falls below 0.4 inches, and ending the month at 2.5 inches, when it rarely exceeds 5.0 inches or falls below 0.5 inches.
Average Monthly Rainfall in December
Over the course of December in Jacksonville, the length of the day is essentially constant. The shortest day of the month is December 21, with 10 hours, 11 minutes of daylight and the longest day is December 1, with 10 hours, 20 minutes of daylight.
Hours of Daylight and Twilight in December
The earliest sunrise of the month in Jacksonville is 7:05 AM on December 1 and the latest sunrise is 17 minutes later at 7:23 AM on December 31.
The earliest sunset is 5:25 PM on December 2 and the latest sunset is 11 minutes later at 5:36 PM on December 31.
Daylight saving time is observed in Jacksonville 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 6:25 AM and sets 14 hours, 6 minutes later, at 8:31 PM, while on December 21, the shortest day of the year, it rises at 7:19 AM and sets 10 hours, 11 minutes later, at 5:30 PM.
Sunrise & Sunset with Twilight and Daylight Saving Time 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 Jacksonville is decreasing during December, falling from 12% to 5% over the course of the month.
For reference, on August 5, the muggiest day of the year, there are muggy conditions 99% of the time, while on January 29, the least muggy day of the year, there are muggy conditions 2% of the time.
Humidity Comfort Levels in December
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 Jacksonville is essentially constant during December, remaining within 0.1 miles per hour of 7.2 miles per hour throughout.
For reference, on February 26, the windiest day of the year, the daily average wind speed is 7.7 miles per hour, while on August 5, the calmest day of the year, the daily average wind speed is 5.5 miles per hour.
The lowest daily average wind speed during December is 7.1 miles per hour on December 17.
Average Wind Speed in December
Wind Direction in December
Jacksonville 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 Jacksonville is gradually decreasing during December, falling by 3°F, from 70°F to 67°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 Jacksonville typically lasts for 11 months (319 days), from around February 9 to around December 25, rarely starting after March 5, or ending before December 3.
During December in Jacksonville, the chance that a given day is within the growing season is very rapidly decreasing falling from 92% to 38% 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 Jacksonville are increasing during December, increasing by 277°F, from 6,800°F to 7,078°F, over the course of the month.
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 Jacksonville is essentially constant during December, remaining within 0.1 kWh of 3.2 kWh throughout.
The lowest average daily incident shortwave solar energy during December is 3.1 kWh on December 21.
Average Daily Incident Shortwave Solar Energy in December
For the purposes of this report, the geographical coordinates of Jacksonville are 30.332 deg latitude, -81.656 deg longitude, and 13 ft elevation.
The topography within 2 miles of Jacksonville is essentially flat, with a maximum elevation change of 39 feet and an average elevation above sea level of 11 feet. Within 10 miles is also essentially flat (92 feet). Within 50 miles is essentially flat (285 feet).
The area within 2 miles of Jacksonville is covered by artificial surfaces (89%) and water (10%), within 10 miles by artificial surfaces (67%) and herbaceous vegetation (13%), and within 50 miles by water (32%) and trees (32%).
This report illustrates the typical weather in Jacksonville 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 Jacksonville.
For each station, the records are corrected for the elevation difference between that station and Jacksonville 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 Jacksonville is computed as the weighted average of the individual contributions from each station, with weights proportional to the inverse of the distance between Jacksonville and a given station.
The stations contributing to this reconstruction are: Jacksonville, Naval Air Station (39%, 11 kilometers, south); Craig Municipal Airport (29%, 14 kilometers, east); Jacksonville International Airport (18%, 18 kilometers, north); and Herlong Recreational Airport (14%, 22 kilometers, west).
All data relating to the Sun's position (e.g., sunrise and sunset) are computed using astronomical formulas from the book, Astronomical Tables of the Sun, Moon and Planets , 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 aiports 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.