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Climate and Average Weather Year Round in New Castle Colorado, United States

In New Castle, the summers are warm and mostly clear, the winters are freezing and partly cloudy, and it is dry year round. Over the course of the year, the temperature typically varies from 12°F to 87°F and is rarely below -2°F or above 93°F.

Based on the tourism score, the best time of year to visit New Castle for warm-weather activities is from late June to late August.

Climate in New Castle

very coldcoldcoolwarmhotwarmcoolcoldvery coldJanFebMarAprMayJunJulAugSepOctNovDecNowNow77%77%51%51%clearovercastprecipitation: 1.4 inprecipitation: 1.4 in0.7 in0.7 inmuggy: 0%muggy: 0%drydrytourism score: 6.2tourism score: 6.20.00.0
New Castle weather by month. Click on each chart for more information.

Average Temperature in New Castle

The hot season lasts for 3.4 months, from June 2 to September 15, with an average daily high temperature above 76°F. The hottest day of the year is July 12, with an average high of 87°F and low of 53°F.

The cold season lasts for 3.1 months, from November 22 to February 25, with an average daily high temperature below 44°F. The coldest day of the year is January 7, with an average low of 12°F and high of 33°F.

Average High and Low Temperature in New Castle

Average High and Low Temperature in New CastlehotcoldcoldJanFebMarAprMayJunJulAugSepOctNovDec-10°F-10°F0°F0°F10°F10°F20°F20°F30°F30°F40°F40°F50°F50°F60°F60°F70°F70°F80°F80°F90°F90°F100°F100°FJan 733°FJan 733°FJul 1287°FJul 1287°F12°F12°F53°F53°FJun 276°FJun 276°FSep 1576°FSep 1576°FNov 2244°FNov 2244°FFeb 2544°FFeb 2544°F44°F44°F45°F45°F22°F22°F21°F21°FNowNow
The daily average high (red line) and low (blue line) temperature, with 25th to 75th and 10th to 90th percentile bands. The thin dotted lines are the corresponding average perceived temperatures.

The figure below shows you a compact characterization of the entire year of hourly average temperatures. The horizontal axis is the day of the year, 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 New Castle

Average Hourly Temperature in New CastleJanFebMarAprMayJunJulAugSepOctNovDec12 AM12 AM4 AM4 AM8 AM8 AM12 PM12 PM4 PM4 PM8 PM8 PM12 AM12 AMNowNowfreezingfreezingvery coldcoldcoolcoolwarmcomfortablevery cold
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 average hourly temperature, color coded into bands. The shaded overlays indicate night and civil twilight.

Hacıbektaş, Turkey (6,513 miles away) and Fareydūnshahr, Iran (7,234 miles) are the far-away foreign places with temperatures most similar to New Castle (view comparison).

Compare New Castle to another city:

Clouds

In New Castle, the average percentage of the sky covered by clouds experiences significant seasonal variation over the course of the year.

The clearer part of the year in New Castle begins around May 30 and lasts for 5.0 months, ending around October 30. On September 13, the clearest day of the year, the sky is clear, mostly clear, or partly cloudy 77% of the time, and overcast or mostly cloudy 23% of the time.

The cloudier part of the year begins around October 30 and lasts for 7.0 months, ending around May 30. On February 21, the cloudiest day of the year, the sky is overcast or mostly cloudy 49% of the time, and clear, mostly clear, or partly cloudy 51% of the time.

Cloud Cover Categories in New Castle

Cloud Cover Categories in New CastleclearercloudiercloudierJanFebMarAprMayJunJulAugSepOctNovDec0%100%10%90%20%80%30%70%40%60%50%50%60%40%70%30%80%20%90%10%100%0%Sep 1377%Sep 1377%Feb 2151%Feb 2151%May 3063%May 3063%Oct 3064%Oct 3064%NowNowclearmostly clearpartly cloudymostly cloudyovercast
0% clear 20% mostly clear 40% partly cloudy 60% mostly cloudy 80% overcast 100%
The percentage of time spent in each cloud cover band, categorized by the percentage of the sky covered by clouds.

Precipitation

A wet day is one with at least 0.04 inches of liquid or liquid-equivalent precipitation. The chance of wet days in New Castle varies throughout the year.

The wetter season lasts 10 months, from July 9 to May 23, with a greater than 18% chance of a given day being a wet day. The chance of a wet day peaks at 24% on May 1.

The drier season lasts 1.5 months, from May 23 to July 9. The smallest chance of a wet day is 12% on June 19.

Among wet days, we distinguish between those that experience rain alone, snow alone, or a mixture of the two. Based on this categorization, the most common form of precipitation in New Castle changes throughout the year.

Rain alone is the most common for 9.5 months, from February 11 to November 28. The highest chance of a day with rain alone is 23% on August 1.

Snow alone is the most common for 2.1 months, from December 1 to February 2. The highest chance of a day with snow alone is 8% on December 29.

Mixed snow and rain is the most common for 1.7 weeks, from February 2 to February 11 and from November 28 to December 1. The highest chance of a day with mixed snow and rain is 6% on February 24.

Daily Chance of Precipitation in New Castle

Daily Chance of Precipitation in New CastlesnowrainsnowJanFebMarAprMayJunJulAugSepOctNovDec0%0%10%10%20%20%30%30%40%40%50%50%60%60%70%70%80%80%90%90%100%100%May 124%May 124%Jun 1912%Jun 1912%Feb 215%Feb 215%Nov 2816%Nov 2816%NowNowsnowrainmixed
The percentage of days in which various types of precipitation are observed, excluding trace quantities: rain alone, snow alone, and mixed (both rain and snow fell in the same day).

Rainfall

To show variation within the months and not just the monthly totals, we show the rainfall accumulated over a sliding 31-day period centered around each day of the year. New Castle experiences some seasonal variation in monthly rainfall.

The rainy period of the year lasts for 10 months, from February 9 to December 9, with a sliding 31-day rainfall of at least 0.5 inches. The most rain falls during the 31 days centered around September 30, with an average total accumulation of 1.4 inches.

The rainless period of the year lasts for 2.0 months, from December 9 to February 9. The least rain falls around January 17, with an average total accumulation of 0.3 inches.

Average Monthly Rainfall in New Castle

Average Monthly Rainfall in New CastlerainJanFebMarAprMayJunJulAugSepOctNovDec0.0 in0.0 in0.5 in0.5 in1.0 in1.0 in1.5 in1.5 in2.0 in2.0 in2.5 in2.5 in3.0 in3.0 inSep 301.4 inSep 301.4 inJan 170.3 inJan 170.3 inMay 11.3 inMay 11.3 inJul 291.0 inJul 291.0 inDec 90.5 inDec 90.5 inNowNow
The average rainfall (solid line) accumulated over the course of a sliding 31-day period centered on the day in question, with 25th to 75th and 10th to 90th percentile bands. The thin dotted line is the corresponding average liquid-equivalent snowfall.

Snowfall

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. Colder, drier snow tends to be on the higher end of that range and warmer, wetter snow on the lower end.

As with rainfall, we consider the snowfall accumulated over a sliding 31-day period centered around each day of the year. New Castle experiences some seasonal variation in monthly liquid-equivalent snowfall.

The snowy period of the year lasts for 5.4 months, from October 24 to April 7, with a sliding 31-day liquid-equivalent snowfall of at least 0.1 inches. The most snow falls during the 31 days centered around January 3, with an average total liquid-equivalent accumulation of 0.5 inches.

The snowless period of the year lasts for 6.5 months, from April 7 to October 24. The least snow falls around July 28, with an average total liquid-equivalent accumulation of 0.0 inches.

Average Liquid-Equivalent Monthly Snowfall in New Castle

Average Liquid-Equivalent Monthly Snowfall in New CastlesnowsnowJanFebMarAprMayJunJulAugSepOctNovDec0.0 in0.0 in0.2 in0.2 in0.4 in0.4 in0.6 in0.6 in0.8 in0.8 in1.0 in1.0 in1.2 in1.2 in1.4 in1.4 inJan 30.5 inJan 30.5 inJul 280.0 inJul 280.0 inOct 240.1 inOct 240.1 inApr 70.1 inApr 70.1 in
The average liquid-equivalent snowfall (solid line) accumulated over the course of a sliding 31-day period centered on the day in question, with 25th to 75th and 10th to 90th percentile bands. The thin dotted line is the corresponding average rainfall.

Sun

The length of the day in New Castle varies significantly over the course of the year. In 2021, the shortest day is December 21, with 9 hours, 22 minutes of daylight; the longest day is June 20, with 14 hours, 58 minutes of daylight.

Hours of Daylight and Twilight in New Castle

Hours of Daylight and Twilight in New CastleJanFebMarAprMayJunJulAugSepOctNovDec0 hr24 hr4 hr20 hr8 hr16 hr12 hr12 hr16 hr8 hr20 hr4 hr24 hr0 hr12 hr, 7 minMar 2012 hr, 7 minMar 2014 hr, 58 minJun 2014 hr, 58 minJun 2012 hr, 8 minSep 2212 hr, 8 minSep 229 hr, 22 minDec 219 hr, 22 minDec 21nightnightdayNowNow
The number of hours during which the Sun is visible (black line). From bottom (most yellow) to top (most gray), the color bands indicate: full daylight, twilight (civil, nautical, and astronomical), and full night.

The earliest sunrise is at 5:42 AM on June 13, and the latest sunrise is 2 hours, 2 minutes later at 7:44 AM on November 6. The earliest sunset is at 4:45 PM on December 7, and the latest sunset is 3 hours, 56 minutes later at 8:41 PM on June 27.

Daylight saving time (DST) is observed in New Castle during 2021, starting in the spring on March 14, lasting 7.8 months, and ending in the fall on November 7.

Sunrise & Sunset with Twilight and Daylight Saving Time in New Castle

Sunrise & Sunset with Twilight and Daylight Saving Time in New CastleJanFebMarAprMayJunJulAugSepOctNovDec12 AM2 AM4 AM6 AM8 AM10 AM12 PM2 PM4 PM6 PM8 PM10 PM12 AMJun 135:42 AMJun 135:42 AM8:41 PMJun 278:41 PMJun 27Dec 74:45 PMDec 74:45 PM7:44 AMNov 67:44 AMNov 6Mar 14DSTMar 14DSTDSTNov 7DSTNov 7daynightnightnightnightSolarMidnightSolarMidnightSolarNoonSunriseSunsetNowNow
The solar day over the course of the year 2021. From bottom to top, the black lines are the previous solar midnight, sunrise, solar noon, sunset, and the next solar midnight. The day, twilights (civil, nautical, and astronomical), and night are indicated by the color bands from yellow to gray. The transitions to and from daylight saving time are indicated by the 'DST' labels.

Moon

The figure below presents a compact representation of key lunar data for 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.

Moon Rise, Set & Phases in New Castle

The time in which the moon is above the horizon (light blue area), with new moons (dark gray lines) and full moons (blue lines) indicated. The shaded overlays indicate night and civil twilight.

Humidity

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 perceived humidity level in New Castle, as measured by the percentage of time in which the humidity comfort level is muggy, oppressive, or miserable, does not vary significantly over the course of the year, remaining a virtually constant 0% throughout.

Humidity Comfort Levels in New Castle

Humidity Comfort Levels in New CastleJanFebMarAprMayJunJulAugSepOctNovDec0%0%10%10%20%20%30%30%40%40%50%50%60%60%70%70%80%80%90%90%100%100%Jul 30%Jul 30%NowNowdrydrycomfortablecomfortable
dry 55°F comfortable 60°F humid 65°F muggy 70°F oppressive 75°F miserable
The percentage of time spent at various humidity comfort levels, categorized by dew point.

Wind

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 New Castle experiences mild seasonal variation over the course of the year.

The windier part of the year lasts for 4.4 months, from February 15 to June 29, with average wind speeds of more than 6.1 miles per hour. The windiest day of the year is April 4, with an average hourly wind speed of 7.0 miles per hour.

The calmer time of year lasts for 7.6 months, from June 29 to February 15. The calmest day of the year is August 7, with an average hourly wind speed of 5.1 miles per hour.

Average Wind Speed in New Castle

Average Wind Speed in New CastlewindyJanFebMarAprMayJunJulAugSepOctNovDec0 mph0 mph2 mph2 mph4 mph4 mph6 mph6 mph8 mph8 mph10 mph10 mph12 mph12 mphApr 47.0 mphApr 47.0 mphAug 75.1 mphAug 75.1 mphFeb 156.1 mphFeb 156.1 mphJun 296.1 mphJun 296.1 mphNowNow
The average of mean hourly wind speeds (dark gray line), with 25th to 75th and 10th to 90th percentile bands.

The predominant average hourly wind direction in New Castle varies throughout the year.

The wind is most often from the west for 6.8 months, from March 11 to October 5, with a peak percentage of 42% on June 23. The wind is most often from the south for 5.2 months, from October 5 to March 11, with a peak percentage of 49% on January 1.

Wind Direction in New Castle

Wind Direction in New CastleSWSJanFebMarAprMayJunJulAugSepOctNovDec0%100%20%80%40%60%60%40%80%20%100%0%NowNowwestsoutheastnorth
northeastsouthwest
The percentage of hours in which the mean wind direction is from each of the four cardinal wind directions, excluding hours in which the mean wind speed is less than 1.0 mph. The lightly tinted areas at the boundaries are the percentage of hours spent in the implied intermediate directions (northeast, southeast, southwest, and northwest).

Best Time of Year to Visit

To characterize how pleasant the weather is in New Castle throughout the year, we compute two travel scores.

The tourism score favors clear, rainless days with perceived temperatures between 65°F and 80°F. Based on this score, the best time of year to visit New Castle for general outdoor tourist activities is from late June to late August, with a peak score in the last week of July.

Tourism Score in New Castle

Tourism Score in New Castlebest timeJanFebMarAprMayJunJulAugSepOctNovDec002244668810106.26.20.00.0NowNowprecipitationprecipitationcloudscloudstemperaturetemperature tourism score
The tourism score (filled area), and its constituents: the temperature score (red line), the cloud cover score (blue line), and the precipitation score (green line).

The beach/pool score favors clear, rainless days with perceived temperatures between 75°F and 90°F. Based on this score, the best time of year to visit New Castle for hot-weather activities is from late June to mid August, with a peak score in the second week of July.

Beach/Pool Score in New Castle

Beach/Pool Score in New Castlebest timeJanFebMarAprMayJunJulAugSepOctNovDec002244668810103.73.70.00.0NowNowprecipitationprecipitationcloudsclouds beach/pool score
The beach/pool score (filled area), and its constituents: the temperature score (red line), the cloud cover score (blue line), and the precipitation score (green line).

Methodology

For each hour between 8:00 AM and 9:00 PM of each day in the analysis period (1980 to 2016), independent scores are computed for perceived temperature, cloud cover, and total precipitation. Those scores are combined into a single hourly composite score, which is then aggregated into days, averaged over all the years in the analysis period, and smoothed.

Our cloud cover score is 10 for fully clear skies, falling linearly to 9 for mostly clear skies, and to 1 for fully overcast skies.

Our precipitation score, which is based on the three-hour precipitation centered on the hour in question, is 10 for no precipitation, falling linearly to 9 for trace precipitation, and to 0 for 0.04 inches of precipitation or more.

Our tourism temperature score is 0 for perceived temperatures below 50°F, rising linearly to 9 for 65°F, to 10 for 75°F, falling linearly to 9 for 80°F, and to 1 for 90°F or hotter.

Our beach/pool temperature score is 0 for perceived temperatures below 65°F, rising linearly to 9 for 75°F, to 10 for 82°F, falling linearly to 9 for 90°F, and to 1 for 100°F or hotter.

Growing Season

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 New Castle typically lasts for 4.6 months (140 days), from around May 13 to around September 30, rarely starting before April 24 or after June 2, and rarely ending before September 11 or after October 20.

Time Spent in Various Temperature Bands and the Growing Season in New Castle

Time Spent in Various Temperature Bands and the Growing Season in New Castlegrowing seasonJanFebMarAprMayJunJulAugSepOctNovDec0%100%10%90%20%80%30%70%40%60%50%50%60%40%70%30%80%20%90%10%100%0%May 1350%May 1350%Sep 3050%Sep 3050%Jun 290%Jun 290%Sep 1190%Sep 1190%Apr 2410%Apr 2410%Oct 2010%Oct 2010%0%Dec 70%Dec 7Jul 29100%Jul 29100%NowNowfrigidfreezingvery coldcoldcoolcomfortablewarmhot
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 percentage of time spent in various temperature bands. The black line is the percentage chance that a given day is within the growing season.

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.

Based on growing degree days alone, the first spring blooms in New Castle should appear around April 22, only rarely appearing before April 8 or after May 6.

Growing Degree Days in New Castle

Growing Degree Days in New CastleJanFebMarAprMayJunJulAugSepOctNovDec0°F0°F500°F500°F1,000°F1,000°F1,500°F1,500°F2,000°F2,000°F2,500°F2,500°FApr 2290°FApr 2290°FJul 5900°FJul 5900°FAug 221,800°FAug 221,800°FDec 312,401°FDec 312,401°FNowNow
The average growing degree days accumulated over the course of the year, with 25th to 75th and 10th to 90th percentile bands.

Solar Energy

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 experiences extreme seasonal variation over the course of the year.

The brighter period of the year lasts for 2.5 months, from May 14 to July 30, with an average daily incident shortwave energy per square meter above 7.2 kWh. The brightest day of the year is June 17, with an average of 8.3 kWh.

The darker period of the year lasts for 3.4 months, from November 1 to February 13, with an average daily incident shortwave energy per square meter below 3.6 kWh. The darkest day of the year is December 21, with an average of 2.4 kWh.

Average Daily Incident Shortwave Solar Energy in New Castle

Average Daily Incident Shortwave Solar Energy in New CastlebrightdarkdarkJanFebMarAprMayJunJulAugSepOctNovDec0 kWh0 kWh1 kWh1 kWh2 kWh2 kWh3 kWh3 kWh4 kWh4 kWh5 kWh5 kWh6 kWh6 kWh7 kWh7 kWh8 kWh8 kWh9 kWh9 kWh10 kWh10 kWhJun 178.3 kWhJun 178.3 kWhDec 212.4 kWhDec 212.4 kWhJul 307.2 kWhJul 307.2 kWhNov 13.6 kWhNov 13.6 kWhFeb 133.6 kWhFeb 133.6 kWhNowNow
The average daily shortwave solar energy reaching the ground per square meter (orange line), with 25th to 75th and 10th to 90th percentile bands.

Topography

For the purposes of this report, the geographical coordinates of New Castle are 39.573 deg latitude, -107.536 deg longitude, and 5,587 ft elevation.

The topography within 2 miles of New Castle contains very significant variations in elevation, with a maximum elevation change of 1,673 feet and an average elevation above sea level of 5,950 feet. Within 10 miles contains very significant variations in elevation (5,469 feet). Within 50 miles also contains extreme variations in elevation (9,308 feet).

The area within 2 miles of New Castle is covered by shrubs (69%) and trees (19%), within 10 miles by trees (52%) and shrubs (39%), and within 50 miles by trees (55%) and shrubs (37%).

Data Sources

This report illustrates the typical weather in New Castle, 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 New Castle.

For each station, the records are corrected for the elevation difference between that station and New Castle 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 New Castle is computed as the weighted average of the individual contributions from each station, with weights proportional to the inverse of the distance between New Castle and a given station.

The stations contributing to this reconstruction are: Garfield County Regional Airport (KRIL, 86%, 17 kilometers, west); Sunlight (K5SM, 3.0%, 20 kilometers, southeast); and Meeker Airport (KEEO, 11%, 61 kilometers, northwest).

Other Data

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.

Disclaimer

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.