August Weather in Glacier Bay National Park and Preserve United StatesDaily high temperatures decrease by 3°F, from 64°F to 60°F, rarely falling below 55°F or exceeding 71°F. The highest daily average high temperature is 64°F on August 1. Daily low temperatures decrease by 3°F, from 51°F to 48°F, rarely falling below 41°F or exceeding 55°F. For reference, on July 31, the hottest day of the year, temperatures in Glacier Bay National Park and Preserve typically range from 51°F to 64°F, while on December 30, the coldest day of the year, they range from 25°F to 34°F. The figure below shows you a compact characterization of the hourly average temperatures for the quarter of the year centered on August. 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. CloudsThe month of August in Glacier Bay National Park and Preserve experiences gradually increasing cloud cover, with the percentage of time that the sky is overcast or mostly cloudy increasing from 64% to 68%. The lowest chance of overcast or mostly cloudy conditions is 64% on August 5. The clearest day of the month is August 5, with clear, mostly clear, or partly cloudy conditions 36% of the time. For reference, on January 26, the cloudiest day of the year, the chance of overcast or mostly cloudy conditions is 79%, while on August 5, the clearest day of the year, the chance of clear, mostly clear, or partly cloudy skies is 36%. PrecipitationA wet day is one with at least 0.04 inches of liquid or liquid-equivalent precipitation. In Glacier Bay National Park and Preserve, the chance of a wet day over the course of August is very rapidly increasing, starting the month at 47% and ending it at 60%. For reference, the year's highest daily chance of a wet day is 71% on October 13, and its lowest chance is 42% on June 22. 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 August in Glacier Bay National Park and Preserve is very rapidly increasing, starting the month at 6.3 inches, when it rarely exceeds 10.0 inches or falls below 2.5 inches, and ending the month at 10.2 inches, when it rarely exceeds 15.2 inches or falls below 5.2 inches. SunOver the course of August in Glacier Bay National Park and Preserve, the length of the day is very rapidly decreasing. From the start to the end of the month, the length of the day decreases by 2 hours, 25 minutes, implying an average daily decrease of 4 minutes, 50 seconds, and weekly decrease of 33 minutes, 50 seconds. The shortest day of the month is August 31, with 14 hours, 2 minutes of daylight and the longest day is August 1, with 16 hours, 27 minutes of daylight. The earliest sunrise of the month in Glacier Bay National Park and Preserve is 4:59 AM on August 1 and the latest sunrise is 1 hour, 6 minutes later at 6:06 AM on August 31. The latest sunset is 9:27 PM on August 1 and the earliest sunset is 1 hour, 19 minutes earlier at 8:08 PM on August 31. Daylight saving time is observed in Glacier Bay National Park and Preserve during 2024, but it neither starts nor ends during August, so the entire month is in standard time. For reference, on June 20, the longest day of the year, the Sun rises at 3:59 AM and sets 18 hours, 21 minutes later, at 10:20 PM, while on December 21, the shortest day of the year, it rises at 8:56 AM and sets 6 hours, 19 minutes later, at 3:16 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 August 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 Glacier Bay National Park and Preserve is essentially constant during August, remaining around 0% throughout. For reference, on June 26, 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. 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 Glacier Bay National Park and Preserve is increasing during August, increasing from 5.6 miles per hour to 6.9 miles per hour over the course of the month. For reference, on December 29, the windiest day of the year, the daily average wind speed is 11.5 miles per hour, while on July 6, the calmest day of the year, the daily average wind speed is 5.5 miles per hour. The hourly average wind direction in Glacier Bay National Park and Preserve throughout August is predominantly from the south, with a peak proportion of 43% on August 6. Water TemperatureGlacier Bay National Park and Preserve 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 Glacier Bay National Park and Preserve is essentially constant during August, remaining around 55°F throughout. The highest average surface water temperature during August is 55°F on August 12. 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 Glacier Bay National Park and Preserve typically lasts for 4.7 months (142 days), from around May 12 to around October 1, rarely starting before April 22 or after May 29, and rarely ending before September 9 or after October 24. The month of August in Glacier Bay National Park and Preserve is very likely fully within the growing season, with the chance that a given day is in the growing season gradually decreasing from 100% to 97% over the course of the month. 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 Glacier Bay National Park and Preserve are gradually increasing during August, increasing by 172°F, from 385°F to 557°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 in Glacier Bay National Park and Preserve is decreasing during August, falling by 1.4 kWh, from 4.4 kWh to 3.0 kWh, over the course of the month. TopographyFor the purposes of this report, the geographical coordinates of Glacier Bay National Park and Preserve are 58.501 deg latitude, -137.001 deg longitude, and 0 ft elevation. The topography within 2 miles of Glacier Bay National Park and Preserve is essentially flat, with a maximum elevation change of 0 feet and an average elevation above sea level of 0 feet. Within 10 miles is also essentially flat (0 feet). Within 50 miles is also essentially flat (0 feet). The area within 2 miles of Glacier Bay National Park and Preserve is covered by snow and glaciers (80%) and bare soil (19%), within 10 miles by snow and glaciers (52%) and trees (15%), and within 50 miles by water (52%) and snow and glaciers (19%). Data SourcesThis report illustrates the typical weather in Glacier Bay National Park and Preserve, based on a statistical analysis of historical hourly weather reports and model reconstructions from January 1, 1980 to December 31, 2016. The details of the data sources used for this report can be found on the Gustavus Airport page. 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. |