May Weather at Vamc Heliport Texas, United StatesDaily high temperatures increase by 6°F, from 81°F to 87°F, rarely falling below 74°F or exceeding 94°F. Daily low temperatures increase by 7°F, from 59°F to 66°F, rarely falling below 48°F or exceeding 72°F. For reference, on August 5, the hottest day of the year, temperatures at Vamc Heliport typically range from 71°F to 93°F, while on January 6, the coldest day of the year, they range from 36°F to 60°F. The figure below shows you a compact characterization of the hourly average temperatures for the quarter of the year centered on May. 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. San Juan, Argentina (4,707 miles away) and Al Quwayrah, Jordan (7,339 miles) are the far-away foreign places with temperatures most similar to Vamc Heliport (view comparison). CloudsThe month of May at Vamc Heliport experiences gradually decreasing cloud cover, with the percentage of time that the sky is overcast or mostly cloudy decreasing from 37% to 30%. The clearest day of the month is May 31, with clear, mostly clear, or partly cloudy conditions 70% of the time. For reference, on January 3, the cloudiest day of the year, the chance of overcast or mostly cloudy conditions is 46%, while on June 14, the clearest day of the year, the chance of clear, mostly clear, or partly cloudy skies is 73%. PrecipitationA wet day is one with at least 0.04 inches of liquid or liquid-equivalent precipitation. At Vamc Heliport, the chance of a wet day over the course of May is increasing, starting the month at 27% and ending it at 32%. For reference, the year's highest daily chance of a wet day is 33% on May 27, and its lowest chance is 12% on December 12. RainfallTo 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 May at Vamc Heliport is increasing, starting the month at 2.8 inches, when it rarely exceeds 5.1 inches or falls below 0.6 inches, and ending the month at 3.6 inches, when it rarely exceeds 7.6 inches or falls below 0.7 inches. The highest average 31-day accumulation is 3.7 inches on May 24. SunOver the course of May at Vamc Heliport, the length of the day is increasing. From the start to the end of the month, the length of the day increases by 36 minutes, implying an average daily increase of 1 minute, 11 seconds, and weekly increase of 8 minutes, 20 seconds. The shortest day of the month is May 1, with 13 hours, 21 minutes of daylight and the longest day is May 31, with 13 hours, 57 minutes of daylight. The latest sunrise of the month at Vamc Heliport is 6:53 AM on May 1 and the earliest sunrise is 17 minutes earlier at 6:35 AM on May 31. The earliest sunset is 8:14 PM on May 1 and the latest sunset is 19 minutes later at 8:32 PM on May 31. Daylight saving time is observed at Vamc Heliport during 2024, but it neither starts nor ends during May, so the entire month is in standard time. For reference, on June 20, the longest day of the year, the Sun rises at 6:35 AM and sets 14 hours, 5 minutes later, at 8:40 PM, while on December 21, the shortest day of the year, it rises at 7:28 AM and sets 10 hours, 13 minutes later, at 5:41 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 May 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 at Vamc Heliport is very rapidly increasing during May, rising from 24% to 52% over the course of the month. For reference, on June 25, 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 at Vamc Heliport is essentially constant during May, remaining within 0.2 miles per hour of 11.0 miles per hour throughout. For reference, on April 1, the windiest day of the year, the daily average wind speed is 11.6 miles per hour, while on September 7, the calmest day of the year, the daily average wind speed is 8.6 miles per hour. The hourly average wind direction at Vamc Heliport throughout May is predominantly from the south, with a peak proportion of 72% on May 31. 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 at Vamc Heliport typically lasts for 7.9 months (242 days), from around March 15 to around November 12, rarely starting before February 18 or after April 8, and rarely ending before October 23 or after December 2. The month of May at Vamc Heliport 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 at Vamc Heliport are rapidly increasing during May, increasing by 667°F, from 1,089°F to 1,756°F, over the course of the month. 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 at Vamc Heliport is essentially constant during May, remaining within 0.2 kWh of 6.7 kWh throughout. TopographyFor the purposes of this report, the geographical coordinates of Vamc Heliport are 30.014 deg latitude, -99.113 deg longitude, and 1,598 ft elevation. The topography within 2 miles of Vamc Heliport contains only modest variations in elevation, with a maximum elevation change of 397 feet and an average elevation above sea level of 1,666 feet. Within 10 miles contains only modest variations in elevation (728 feet). Within 50 miles contains significant variations in elevation (1,739 feet). The area within 2 miles of Vamc Heliport is covered by shrubs (43%), grassland (31%), and artificial surfaces (13%), within 10 miles by shrubs (48%) and grassland (30%), and within 50 miles by shrubs (49%) and grassland (25%). Data SourcesThis report illustrates the typical weather at Vamc Heliport, based on a statistical analysis of historical hourly weather reports and model reconstructions from January 1, 1980 to December 31, 2016. Temperature and Dew PointVamc Heliport 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 Gillespie County Airport, Hondo Municipal Airport, San Antonio International Airport, Kelly Field Annex, Kimble County Airport, Stinson Municipal Airport, Horseshoe Bay Resort Airport, and Llano Municipal Airport. 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. 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