Average Weather in December at Catalina Airport California, United States
The lowest daily average high temperature is 64°F on December 24.
Daily low temperatures are around 54°F, rarely falling below 46°F or exceeding 62°F. The lowest daily average low temperature is 53°F on December 24.
For reference, on August 24, the hottest day of the year, temperatures at Catalina Airport typically range from 67°F to 81°F, while on March 18, the coldest day of the year, they range from 52°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
The month of December at Catalina Airport experiences essentially constant cloud cover, with the percentage of time that the sky is overcast or mostly cloudy remaining about 36% throughout the month. The highest chance of overcast or mostly cloudy conditions is 39% on December 28.
The clearest day of the month is December 1, with clear, mostly clear, or partly cloudy conditions 66% of the time.
For reference, on February 20, the cloudiest day of the year, the chance of overcast or mostly cloudy conditions is 41%, while on September 7, the clearest day of the year, the chance of clear, mostly clear, or partly cloudy skies is 91%.
Cloud Cover Categories in December
A wet day is one with at least 0.04 inches of liquid or liquid-equivalent precipitation. At Catalina Airport, the chance of a wet day over the course of December is rapidly increasing, starting the month at 11% and ending it at 18%.
For reference, the year's highest daily chance of a wet day is 20% on February 20, and its lowest chance is 0% on July 16.
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 at Catalina Airport is increasing, starting the month at 1.4 inches, when it rarely exceeds 3.2 inches, and ending the month at 2.3 inches, when it rarely exceeds 6.6 inches or falls below 0.1 inches.
Average Monthly Rainfall in December
Over the course of December at Catalina Airport, the length of the day is essentially constant. The shortest day of the month is December 21, with 9 hours, 56 minutes of daylight and the longest day is December 1, with 10 hours, 6 minutes of daylight.
Hours of Daylight and Twilight in December
The earliest sunrise of the month at Catalina Airport is 6:39 AM on December 1 and the latest sunrise is 18 minutes later at 6:57 AM on December 31.
The earliest sunset is 4:45 PM on December 4 and the latest sunset is 11 minutes later at 4:56 PM on December 31.
Daylight saving time is observed at Catalina Airport 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 5:44 AM and sets 14 hours, 22 minutes later, at 8:06 PM, while on December 21, the shortest day of the year, it rises at 6:53 AM and sets 9 hours, 56 minutes later, at 4:50 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 at Catalina Airport is essentially constant during December, remaining around 0% throughout.
For reference, on August 28, the muggiest day of the year, there are muggy conditions 3% 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
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 at Catalina Airport is essentially constant during December, remaining within 0.2 miles per hour of 9.0 miles per hour throughout.
For reference, on April 11, the windiest day of the year, the daily average wind speed is 9.7 miles per hour, while on August 5, the calmest day of the year, the daily average wind speed is 6.7 miles per hour.
The highest daily average wind speed during December is 9.1 miles per hour on December 11.
Average Wind Speed in December
Wind Direction in December
Catalina Airport 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 at Catalina Airport is gradually decreasing during December, falling by 2°F, from 62°F to 59°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).
Temperatures at Catalina Airport are sufficiently warm year round that it is not entirely meaningful to discuss the growing season in these terms. We nevertheless include the chart below as an illustration of the distribution of temperatures experienced throughout the year.
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 at Catalina Airport are increasing during December, increasing by 259°F, from 4,792°F to 5,051°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 at Catalina Airport is essentially constant during December, remaining within 0.1 kWh of 3.1 kWh throughout.
The lowest average daily incident shortwave solar energy during December is 3.0 kWh on December 26.
Average Daily Incident Shortwave Solar Energy in December
For the purposes of this report, the geographical coordinates of Catalina Airport are 33.404 deg latitude, -118.416 deg longitude, and 666 ft elevation.
The topography within 2 miles of Catalina Airport contains large variations in elevation, with a maximum elevation change of 2,008 feet and an average elevation above sea level of 938 feet. Within 10 miles also contains large variations in elevation (2,067 feet). Within 50 miles also contains large variations in elevation (2,802 feet).
The area within 2 miles of Catalina Airport is covered by shrubs (65%) and water (18%), within 10 miles by water (76%) and shrubs (14%), and within 50 miles by water (81%) and artificial surfaces (14%).
This report illustrates the typical weather at Catalina Airport 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
Catalina Airport has a weather station that reported reliably enough during the analysis period that we have included it in our network. When available, historical temperature and dew point measurements are taken directly from this weather station. These records are obtained from NOAA's Integrated Surface Hourly data set, falling back on ICAO METAR records as required.
In the case of missing or erroneous measurements from this station, we fall back on records from nearby stations, adjusted according to typical seasonal and diurnal intra-station differences. For a given day of the year and hour of the day, the fallback station is selected to minimize the prediction error over the years for which there are measurements for both stations.
The stations on which we may fall back include but are not limited to San Clemente Island, San Clemente Island NALF; Long Beach; Long Beach Airport; Jack Northrop Field/Hawthorne Municipal Airport; McDonnell Douglas Space Systems Heliport; Los Angeles International Airport; Santa Monica Municipal Airport; and John Wayne Airport-Orange County.
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.