Summer Weather in Arlington Virginia, United StatesDaily high temperatures are around 83°F, rarely falling below 69°F or exceeding 95°F. The highest daily average high temperature is 87°F on July 20. Daily low temperatures increase by 5°F, from 62°F to 66°F, rarely falling below 53°F or exceeding 76°F. The highest daily average low temperature is 71°F on July 20. For reference, on July 20, the hottest day of the year, temperatures in Arlington typically range from 71°F to 87°F, while on January 30, the coldest day of the year, they range from 28°F to 43°F. The figure below shows you a compact characterization of the hourly average summer 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. Belokany, Azerbaijan (5,840 miles away) is the far-away foreign place with temperatures most similar to Arlington (view comparison). CloudsThe summer in Arlington experiences rapidly decreasing cloud cover, with the percentage of time that the sky is overcast or mostly cloudy decreasing from 48% to 35%. The clearest day of the summer is August 28, with clear, mostly clear, or partly cloudy conditions 65% of the time. For reference, on January 5, the cloudiest day of the year, the chance of overcast or mostly cloudy conditions is 52%, while on September 22, the clearest day of the year, the chance of clear, mostly clear, or partly cloudy skies is 65%. PrecipitationA wet day is one with at least 0.04 inches of liquid or liquid-equivalent precipitation. In Arlington, the chance of a wet day over the course of the summer is very rapidly decreasing, starting the season at 37% and ending it at 28%. For reference, the year's highest daily chance of a wet day is 40% on June 16, and its lowest chance is 20% on October 19. RainfallTo 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 summer in Arlington is gradually decreasing, starting the season at 3.5 inches, when it rarely exceeds 6.1 inches or falls below 1.4 inches, and ending the season at 3.1 inches, when it rarely exceeds 5.3 inches or falls below 1.0 inches. The lowest average 31-day accumulation is 3.0 inches on August 25. SunOver the course of the summer in Arlington, the length of the day is rapidly decreasing. From the start to the end of the season, the length of the day decreases by 1 hour, 41 minutes, implying an average daily decrease of 1 minute, 7 seconds, and weekly decrease of 7 minutes, 46 seconds. The shortest day of the summer is August 31, with 13 hours, 2 minutes of daylight and the longest day is June 20, with 14 hours, 54 minutes of daylight. The earliest sunrise of the summer in Arlington is 5:42 AM on June 13 and the latest sunrise is 54 minutes later at 6:36 AM on August 31. The latest sunset is 8:37 PM on June 27 and the earliest sunset is 58 minutes earlier at 7:39 PM on August 31. Daylight saving time is observed in Arlington during 2024, but it neither starts nor ends during the summer, so the entire season is in daylight saving time. For reference, on June 20, the longest day of the year, the Sun rises at 5:43 AM and sets 14 hours, 54 minutes later, at 8:37 PM, while on December 21, the shortest day of the year, it rises at 7:23 AM and sets 9 hours, 26 minutes later, at 4:50 PM. The figure below presents a compact representation of the sun's elevation (the angle of the sun above the horizon) and azimuth (its compass bearing) for every hour of every day in the reporting period. The horizontal axis is the day of the year and the vertical axis is the hour of the day. For a given day and hour of that day, the background color indicates the azimuth of the sun at that moment. The black isolines are contours of constant solar elevation. MoonThe figure below presents a compact representation of key lunar data for the summer of 2024. 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. HumidityWe 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 Arlington is rapidly increasing during the summer, rising from 28% to 45% over the course of the season. The highest chance of a muggy day during the summer is 67% on July 27. For reference, on July 27, the muggiest day of the year, there are muggy conditions 67% of the time, while on January 24, the least muggy day of the year, there are muggy conditions 0% of the time. WindThis 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 Arlington is essentially constant during the summer, remaining within 0.5 miles per hour of 6.3 miles per hour throughout. For reference, on February 26, the windiest day of the year, the daily average wind speed is 9.6 miles per hour, while on July 31, the calmest day of the year, the daily average wind speed is 5.7 miles per hour. The lowest daily average wind speed during the summer is 5.7 miles per hour on July 31. The wind direction in Arlington during the summer is predominantly out of the south from June 1 to June 23 and from July 23 to August 31 and the west from June 23 to July 23. Water TemperatureArlington 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 Arlington is very rapidly increasing during the summer, rising by 14°F, from 62°F to 76°F, over the course of the season. The highest average surface water temperature during the summer is 77°F on August 11. Growing SeasonDefinitions 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 Arlington typically lasts for 7.5 months (229 days), from around March 28 to around November 12, rarely starting before March 12 or after April 13, and rarely ending before October 25 or after November 30. The summer in Arlington is reliably fully 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. The average accumulated growing degree days in Arlington are very rapidly increasing during the summer, increasing by 2,330°F, from 846°F to 3,175°F, over the course of the season. Solar EnergyThis 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 Arlington is gradually decreasing during the summer, falling by 0.9 kWh, from 6.6 kWh to 5.7 kWh, over the course of the season. The highest average daily incident shortwave solar energy during the summer is 6.9 kWh on June 22. TopographyFor the purposes of this report, the geographical coordinates of Arlington are 38.881 deg latitude, -77.104 deg longitude, and 266 ft elevation. The topography within 2 miles of Arlington contains only modest variations in elevation, with a maximum elevation change of 420 feet and an average elevation above sea level of 234 feet. Within 10 miles contains only modest variations in elevation (512 feet). Within 50 miles contains significant variations in elevation (2,198 feet). The area within 2 miles of Arlington is covered by artificial surfaces (95%), within 10 miles by artificial surfaces (82%) and trees (12%), and within 50 miles by trees (41%) and cropland (24%). Data SourcesThis report illustrates the typical weather in Arlington, based on a statistical analysis of historical hourly weather reports and model reconstructions from January 1, 1980 to December 31, 2016. Temperature and Dew PointThere are 4 weather stations near enough to contribute to our estimation of the temperature and dew point in Arlington. For each station, the records are corrected for the elevation difference between that station and Arlington 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 Arlington is computed as the weighted average of the individual contributions from each station, with weights proportional to the inverse of the distance between Arlington and a given station. The stations contributing to this reconstruction are:
To get a sense of how much these sources agree with each other, you can view a comparison of Arlington and the stations that contribute to our estimates of its temperature history and climate. Please note that each source's contribution is adjusted for elevation and the relative change present in the MERRA-2 data. Other DataAll 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 © OpenStreetMap contributors. DisclaimerThe 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. Please review our full terms contained on our Terms of Service page. |