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Average Weather at Raleigh-Durham International Airport North Carolina, United States

At Raleigh-Durham International Airport, the summers are hot and muggy, the winters are short and very cold, and it is wet and partly cloudy year round. Over the course of the year, the temperature typically varies from 33°F to 89°F and is rarely below 19°F or above 95°F.

Climate Summary

coldcoolwarmhotwarmcoolcoldJanFebMarAprMayJunJulAugSepOctNovDec65%65%48%48%clearovercastprecipitation: 4.1 inprecipitation: 4.1 in2.7 in2.7 inmuggy: 84%muggy: 84%0%0%drydrytourism score: 6.3tourism score: 6.31.01.0
Click on each chart for more information.

Based on the tourism score, the best times of year to visit Raleigh-Durham International Airport for warm-weather activities are from early May to mid June and from late August to mid October.

Temperature

The hot season lasts for 3.6 months, from May 27 to September 15, with an average daily high temperature above 81°F. The hottest day of the year is July 20, with an average high of 89°F and low of 71°F.

The cool season lasts for 3.0 months, from December 1 to February 28, with an average daily high temperature below 58°F. The coldest day of the year is January 29, with an average low of 33°F and high of 51°F.

Average High and Low Temperature

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

Average Hourly Temperature at Raleigh-Durham International AirportJanFebMarAprMayJunJulAugSepOctNovDec12 AM4 AM8 AM12 PM4 PM8 PM12 AMvery coldvery coldvery coldcoldcoldcoolcoolcomfortablewarmhotvery coldwarm
The average hourly temperature, color coded into bands: 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 shaded overlays indicate night and civil twilight.

Shkodër, Albania (4,993 miles away) and Luoqiao, China (7,984 miles) are the far-away foreign places with temperatures most similar to Raleigh-Durham International Airport (view comparison).

Clouds

At Raleigh-Durham International Airport, the average percentage of the sky covered by clouds experiences mild seasonal variation over the course of the year.

The clearer part of the year at Raleigh-Durham International Airport begins around July 29 and lasts for 3.8 months, ending around November 24. On October 12, the clearest day of the year, the sky is clear, mostly clear, or partly cloudy 65% of the time, and overcast or mostly cloudy 35% of the time.

The cloudier part of the year begins around November 24 and lasts for 8.2 months, ending around July 29. On December 27, the cloudiest day of the year, the sky is overcast or mostly cloudy 52% of the time, and clear, mostly clear, or partly cloudy 48% of the time.

Cloud Cover Categories

Cloud Cover Categories at Raleigh-Durham International AirportclearercloudiercloudierJanFebMarAprMayJunJulAugSepOctNovDec0%100%10%90%20%80%30%70%40%60%50%50%60%40%70%30%80%20%90%10%100%0%Oct 1265%Oct 1265%Dec 2748%Dec 2748%Jul 2956%Jul 2956%clearmostly clearpartly cloudymostly cloudyovercast
The percentage of time spent in each cloud cover band, categorized by the percentage of the sky covered by clouds: clear < 20% < mostly clear < 40% < partly cloudy < 60% < mostly cloudy < 80% < overcast.

Precipitation

A wet day is one with at least 0.04 inches of liquid or liquid-equivalent precipitation. The chance of wet days at Raleigh-Durham International Airport varies throughout the year.

The wetter season lasts 3.6 months, from May 11 to August 30, with a greater than 32% chance of a given day being a wet day. The chance of a wet day peaks at 45% on July 15.

The drier season lasts 8.4 months, from August 30 to May 11. The smallest chance of a wet day is 20% on October 31.

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 throughout the year is rain alone, with a peak probability of 45% on July 15.

Daily Chance of Precipitation

Daily Chance of Precipitation at Raleigh-Durham International AirportwetdrydryJanFebMarAprMayJunJulAugSepOctNovDec0%10%20%30%40%50%60%70%80%90%100%Jul 1545%Jul 1545%Oct 3120%Oct 3120%Jan 126%Jan 126%May 1132%May 1132%Aug 3032%Aug 3032%rainmixed
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. Raleigh-Durham International Airport experiences some seasonal variation in monthly rainfall.

Rain falls throughout the year at Raleigh-Durham International Airport. The most rain falls during the 31 days centered around September 4, with an average total accumulation of 4.1 inches.

The least rain falls around January 30, with an average total accumulation of 2.6 inches.

Average Monthly Rainfall

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. Raleigh-Durham International Airport experiences some seasonal variation in monthly liquid-equivalent snowfall.

The snowy period of the year lasts for 3.1 months, from December 10 to March 14, with a sliding 31-day liquid-equivalent snowfall of at least 0.1 inches. The most snow falls during the 31 days centered around February 5, with an average total liquid-equivalent accumulation of 0.4 inches.

The snowless period of the year lasts for 8.9 months, from March 14 to December 10. The least snow falls around July 23, with an average total liquid-equivalent accumulation of 0.0 inches.

Average Liquid-Equivalent Monthly Snowfall

Average Liquid-Equivalent Monthly Snowfall at Raleigh-Durham International AirportsnowJanFebMarAprMayJunJulAugSepOctNovDec0 in1 in2 in3 in4 inFeb 50.4 inFeb 50.4 inJul 230.0 inJul 230.0 inDec 100.1 inDec 100.1 inMar 140.1 inMar 140.1 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 at Raleigh-Durham International Airport varies significantly over the course of the year. In 2017, the shortest day is December 21, with 9 hours, 43 minutes of daylight; the longest day is June 21, with 14 hours, 36 minutes of daylight.

Hours of Daylight and Twilight

Hours of Daylight and Twilight at Raleigh-Durham International AirportJanFebMarAprMayJunJulAugSepOctNovDec0 hr24 hr4 hr20 hr8 hr16 hr12 hr12 hr16 hr8 hr20 hr4 hr24 hr0 hr12 hr, 6 minMar 2012 hr, 6 minMar 2014 hr, 36 minJun 2114 hr, 36 minJun 2112 hr, 8 minSep 2212 hr, 8 minSep 229 hr, 43 minDec 219 hr, 43 minDec 21nightnightday
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 5:58 AM on June 13, and the latest sunrise is 1 hour, 43 minutes later at 7:40 AM on November 4. The earliest sunset is at 5:01 PM on December 6, and the latest sunset is 3 hours, 35 minutes later at 8:35 PM on June 28.

Daylight saving time (DST) is observed at Raleigh-Durham International Airport during 2017, starting in the spring on March 12, lasting 7.8 months, and ending in the fall on November 5.

Sunrise & Sunset with Twilight and Daylight Saving Time

Sunrise & Sunset with Twilight and Daylight Saving Time at Raleigh-Durham International AirportJanFebMarAprMayJunJulAugSepOctNovDec12 AM2 AM4 AM6 AM8 AM10 AM12 PM2 PM4 PM6 PM8 PM10 PM12 AMJun 135:58 AMJun 135:58 AM8:35 PMJun 288:35 PMJun 28Dec 65:01 PMDec 65:01 PM7:40 AMNov 47:40 AMNov 4Mar 12DSTMar 12DSTDSTNov 5DSTNov 5daynightnightnightnightSolarMidnightSolarMidnightSolarNoonSunriseSunset
The solar day over the course of the year 2017. 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.

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.

Raleigh-Durham International Airport experiences extreme seasonal variation in the perceived humidity.

The muggier period of the year lasts for 4.5 months, from May 20 to October 2, during which time the comfort level is muggy, oppressive, or miserable at least 21% of the time. The muggiest day of the year is July 25, with muggy conditions 84% of the time.

The least muggy day of the year is February 1, when muggy conditions are essentially unheard of.

Humidity Comfort Levels

Humidity Comfort Levels at Raleigh-Durham International AirportmuggyJanFebMarAprMayJunJulAugSepOctNovDec0%10%20%30%40%50%60%70%80%90%100%Feb 10%Feb 10%84%Jul 2584%Jul 25May 2021%May 2021%Oct 221%Oct 221%oppressiveoppressivemuggymuggydrydryhumidhumidmiserablemiserablecomfortablecomfortable
The percentage of time spent at various humidity comfort levels, categorized by dew point: dry < 55°F < comfortable < 60°F < humid < 65°F < muggy < 70°F < oppressive < 75°F < miserable.

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 at Raleigh-Durham International Airport experiences mild seasonal variation over the course of the year.

The windier part of the year lasts for 6.3 months, from November 5 to May 15, with average wind speeds of more than 5.3 miles per hour. The windiest day of the year is February 27, with an average hourly wind speed of 6.5 miles per hour.

The calmer time of year lasts for 5.7 months, from May 15 to November 5. The calmest day of the year is August 9, with an average hourly wind speed of 4.0 miles per hour.

Average Wind Speed

Average Wind Speed at Raleigh-Durham International AirportwindywindyJanFebMarAprMayJunJulAugSepOctNovDec0 mph1 mph2 mph3 mph4 mph5 mph6 mph7 mph8 mph9 mph10 mphFeb 276.5 mphFeb 276.5 mphAug 94.0 mphAug 94.0 mphNov 55.3 mphNov 55.3 mphMay 155.3 mphMay 155.3 mph
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 at Raleigh-Durham International Airport varies throughout the year.

The wind is most often from the west for 2.0 weeks, from January 7 to January 21; for 1.6 weeks, from March 18 to March 29; for 1.3 weeks, from April 30 to May 9; and for 1.7 months, from June 3 to July 25, with a peak percentage of 36% on July 13. The wind is most often from the north for 1.9 months, from January 21 to March 18 and for 4.0 months, from September 8 to January 7, with a peak percentage of 34% on January 29. The wind is most often from the south for 1.0 months, from March 29 to April 30; for 3.6 weeks, from May 9 to June 3; and for 1.0 months, from July 25 to August 26, with a peak percentage of 33% on July 31.

Wind Direction

Wind Direction at Raleigh-Durham International AirportWNWSSWSENJanFebMarAprMayJunJulAugSepOctNovDec0%100%20%80%40%60%60%40%80%20%100%0%westsouthnortheast
The percentage of hours in which the mean wind direction is from each of the four cardinal wind directions (north, east, south, and west), excluding hours in which the mean wind speed is less than 1 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 at Raleigh-Durham International Airport 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 times of year to visit Raleigh-Durham International Airport for general outdoor tourist activities are from early May to mid June and from late August to mid October, with a peak score in the third week of September.

Tourism Score

Tourism Score at Raleigh-Durham International Airportbest timeJanFebMarAprMayJunJulAugSepOctNovDec02468106.36.31.01.05.95.95.05.0 precipitationprecipitationcloudscloudstemperaturetemperaturetourism 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 Raleigh-Durham International Airport for hot-weather activities is from mid June to mid September, with a peak score in the second week of August.

Beach/Pool Score

Beach/Pool Score at Raleigh-Durham International Airportbest timeJanFebMarAprMayJunJulAugSepOctNovDec02468106.06.00.10.1 precipitationprecipitationcloudscloudstemperaturetemperaturebeach/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 at Raleigh-Durham International Airport typically lasts for 7.2 months (221 days), from around March 30 to around November 6, rarely starting before March 8 or after April 21, and rarely ending before October 19 or after November 25.

Time Spent in Various Temperature Bands and the Growing Season

Time Spent in Various Temperature Bands and the Growing Season at Raleigh-Durham International Airportgrowing seasonJanFebMarAprMayJunJulAugSepOctNovDec0%100%10%90%20%80%30%70%40%60%50%50%60%40%70%30%80%20%90%10%100%0%50%Mar 3050%Mar 3050%Nov 650%Nov 690%Apr 2190%Apr 2190%Oct 1990%Oct 1910%Mar 810%Mar 810%Nov 2510%Nov 250%Jan 250%Jan 25Jul 20100%Jul 20100%very coldcoldcoolcomfortablewarmhot
The percentage of time spent in various temperature bands: 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 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 at Raleigh-Durham International Airport should appear around February 17, only rarely appearing before January 29 or after March 9.

Growing Degree Days

Growing Degree Days at Raleigh-Durham International AirportJanFebMarAprMayJunJulAugSepOctNovDec0°F1,000°F2,000°F3,000°F4,000°F5,000°FFeb 1787°FFeb 1787°FMay 17900°FMay 17900°FJun 251,800°FJun 251,800°FDec 314,882°FDec 314,882°F
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 significant seasonal variation over the course of the year.

The brighter period of the year lasts for 4.1 months, from April 15 to August 20, with an average daily incident shortwave energy per square meter above 5.9 kWh. The brightest day of the year is June 23, with an average of 6.8 kWh.

The darker period of the year lasts for 2.9 months, from November 9 to February 7, with an average daily incident shortwave energy per square meter below 3.3 kWh. The darkest day of the year is December 25, with an average of 2.4 kWh.

Average Daily Incident Shortwave Solar Energy

Average Daily Incident Shortwave Solar Energy at Raleigh-Durham International AirportbrightdarkdarkJanFebMarAprMayJunJulAugSepOctNovDec0 kWh1 kWh2 kWh3 kWh4 kWh5 kWh6 kWh7 kWh8 kWh9 kWhJun 236.8 kWhJun 236.8 kWhDec 252.4 kWhDec 252.4 kWhApr 155.9 kWhApr 155.9 kWhAug 205.9 kWhAug 205.9 kWhNov 93.3 kWhNov 93.3 kWhFeb 73.3 kWhFeb 73.3 kWh
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 Raleigh-Durham International Airport are 35.879 deg latitude, -78.787 deg longitude, and 371 ft elevation.

The topography within 2 miles of Raleigh-Durham International Airport contains only modest variations in elevation, with a maximum elevation change of 190 feet and an average elevation above sea level of 371 feet. Within 10 miles also contains only modest variations in elevation (449 feet). Within 50 miles contains only modest variations in elevation (968 feet).

The area within 2 miles of Raleigh-Durham International Airport is covered by artificial surfaces (72%) and trees (25%), within 10 miles by artificial surfaces (57%) and trees (39%), and within 50 miles by trees (57%) and cropland (31%).

Data Sources

This report illustrates the typical weather at Raleigh-Durham International Airport, 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

Raleigh-Durham International 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 Horace Williams Airport; Person County Airport; Sanford, Sanford-Lee County Regional Airport; Louisburg, Franklin County Airport; Erwin, Harnett County Airport; Johnston Regional Airport; Henderson-Oxford Airport; and Burlington-Alamance Regional Airport.

Other Data

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.

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.