Winter Weather in Castle Rock Colorado, United States
Daily high temperatures increase by 2°F, from 45°F to 47°F, rarely falling below 24°F or exceeding 61°F. The lowest daily average high temperature is 40°F on December 30.
Daily low temperatures are around 22°F, rarely falling below 3°F or exceeding 36°F. The lowest daily average low temperature is 19°F on December 30.
For reference, on July 10, the hottest day of the year, temperatures in Castle Rock typically range from 57°F to 83°F, while on December 30, the coldest day of the year, they range from 19°F to 40°F.
Average High and Low Temperature in the Winter in Castle Rock
The figure below shows you a compact characterization of the hourly average winter temperatures. 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 the Winter in Castle Rock
frigid 15°F freezing 32°F very cold 45°F cold 55°F cool 65°F comfortable 75°F warm 85°F hot 95°F sweltering
The winter in Castle Rock experiences essentially constant cloud cover, with the percentage of time that the sky is overcast or mostly cloudy remaining about 42% throughout the season.
The clearest day of the winter is January 9, with clear, mostly clear, or partly cloudy conditions 61% of the time.
For reference, on May 5, the cloudiest day of the year, the chance of overcast or mostly cloudy conditions is 46%, while on September 29, the clearest day of the year, the chance of clear, mostly clear, or partly cloudy skies is 75%.
Cloud Cover Categories in the Winter in Castle Rock
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 Castle Rock, the chance of a wet day over the course of the winter is essentially constant, remaining around 6% throughout.
For reference, the year's highest daily chance of a wet day is 33% on August 4, and its lowest chance is 4% on January 10.
Over the course of the winter in Castle Rock, the chance of a day with only rain remains an essentially constant 1% throughout, the chance of a day with mixed snow and rain remains an essentially constant 1% throughout, and the chance of a day with only snow remains an essentially constant 4% throughout.
Probability of Precipitation in the Winter in Castle Rock
To show variation within the season and not just the monthly totals, we show the rainfall accumulated over a sliding 31-day period centered around each day.
The average sliding 31-day rainfall during the winter in Castle Rock is essentially constant, remaining about 0.1 inches throughout, and rarely exceeding 0.4 inches.
The lowest average 31-day accumulation is 0.0 inches on January 12.
Average Monthly Rainfall in the Winter in Castle Rock
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 the winter in Castle Rock is essentially constant, remaining about 0.2 inches throughout, and rarely exceeding 0.7 inches or falling to 0.0 inches.
The lowest average 31-day liquid-equivalent accumulation is 0.2 inches on January 24.
Average Monthly Liquid-Equivalent Snowfall in the Winter in Castle Rock
Over the course of the winter in Castle Rock, the length of the day is rapidly increasing. From the start to the end of the season, the length of the day increases by 1 hour, 42 minutes, implying an average daily increase of 1 minute, 8 seconds, and weekly increase of 7 minutes, 59 seconds.
The shortest day of the winter is December 21, with 9 hours, 23 minutes of daylight and the longest day is February 28, with 11 hours, 17 minutes of daylight.
Hours of Daylight and Twilight in the Winter in Castle Rock
The latest sunrise of the winter in Castle Rock is 7:19 AM on January 5 and the earliest sunrise is 46 minutes earlier at 6:33 AM on February 28.
The earliest sunset is 4:35 PM on December 7 and the latest sunset is 1 hour, 15 minutes later at 5:50 PM on February 28.
Daylight saving time is observed in Castle Rock during 2021, but it neither starts nor ends during the winter, so the entire season is in standard time.
For reference, on June 21, the longest day of the year, the Sun rises at 5:32 AM and sets 14 hours, 57 minutes later, at 8:29 PM, while on December 21, the shortest day of the year, it rises at 7:16 AM and sets 9 hours, 23 minutes later, at 4:39 PM.
Sunrise & Sunset with Twilight and Daylight Saving Time in the Winter in Castle Rock
The figure below presents a compact representation of key lunar data for the winter of 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 the Winter in Castle Rock
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 Castle Rock is essentially constant during the winter, remaining around 0% throughout.
For reference, on July 27, the muggiest day of the year, there are muggy conditions 0% 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 the Winter in Castle Rock
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 Castle Rock is gradually increasing during the winter, increasing from 8.8 miles per hour to 9.4 miles per hour over the course of the season.
For reference, on April 1, the windiest day of the year, the daily average wind speed is 10.0 miles per hour, while on August 14, the calmest day of the year, the daily average wind speed is 7.1 miles per hour.
Average Wind Speed in the Winter in Castle Rock
The hourly average wind direction in Castle Rock throughout the winter is predominantly from the west, with a peak proportion of 62% on January 11.
Wind Direction in the Winter in Castle Rock
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 Castle Rock typically lasts for 4.8 months (146 days), from around May 9 to around October 2, rarely starting before April 23 or after May 25, and rarely ending before September 12 or after October 22.
The winter in Castle Rock is reliably fully outside of the growing season.
Time Spent in Various Temperature Bands and the Growing Season in the Winter in Castle Rock
frigid 15°F freezing 32°F very cold 45°F cold 55°F cool 65°F comfortable 75°F warm 85°F hot 95°F sweltering
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 Castle Rock are very rapidly decreasing during the winter, decreasing by 2,408°F, from 2,426°F to 19°F, over the course of the season.
Growing Degree Days in the Winter in Castle Rock
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 Castle Rock is rapidly increasing during the winter, rising by 1.7 kWh, from 2.7 kWh to 4.4 kWh, over the course of the season.
The lowest average daily incident shortwave solar energy during the winter is 2.5 kWh on December 22.
Average Daily Incident Shortwave Solar Energy in the Winter in Castle Rock
For the purposes of this report, the geographical coordinates of Castle Rock are 39.372 deg latitude, -104.856 deg longitude, and 6,227 ft elevation.
The topography within 2 miles of Castle Rock contains significant variations in elevation, with a maximum elevation change of 617 feet and an average elevation above sea level of 6,358 feet. Within 10 miles contains significant variations in elevation (2,057 feet). Within 50 miles contains large variations in elevation (9,331 feet).
The area within 2 miles of Castle Rock is covered by shrubs (59%) and grassland (38%), within 10 miles by grassland (69%) and shrubs (24%), and within 50 miles by grassland (44%) and trees (27%).
This report illustrates the typical weather in Castle Rock, 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 Castle Rock.
For each station, the records are corrected for the elevation difference between that station and Castle Rock 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 Castle Rock is computed as the weighted average of the individual contributions from each station, with weights proportional to the inverse of the distance between Castle Rock and a given station.
The stations contributing to this reconstruction are: Arapahoe County Airport (KAPA, 62%, 22 kilometers, north); Elbert Mountain, Monument Pass (KMNH, 34%, 26 kilometers, southeast); and Wilkerson Pass (K4BM, 3.4%, 67 kilometers, southwest).
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.