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Average Weather in Girdwood Alaska, United States

In Girdwood, the summers are cool and overcast; the winters are long, freezing, and mostly cloudy; and it is wet year round. Over the course of the year, the temperature typically varies from 16°F to 64°F and is rarely below -9°F or above 72°F.

Climate Summary

freezingvery coldcoldcoolcoldvery coldfreezingJanFebMarAprMayJunJulAugSepOctNovDec41%41%28%28%overcastclearprecipitation: 7.0 inprecipitation: 7.0 in2.5 in2.5 inmuggy: 0%muggy: 0%drydrytourism score: 2.6tourism score: 2.60.00.0
Click on each chart for more information.

Based on the tourism score, the best time of year to visit Girdwood for warm-weather activities is from early July to early August.

Temperature

The warm season lasts for 3.6 months, from May 22 to September 9, with an average daily high temperature above 57°F. The hottest day of the year is July 7, with an average high of 64°F and low of 49°F.

The cold season lasts for 4.4 months, from November 5 to March 17, with an average daily high temperature below 34°F. The coldest day of the year is January 20, with an average low of 16°F and high of 27°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 in GirdwoodJanFebMarAprMayJunJulAugSepOctNovDec12 AM4 AM8 AM12 PM4 PM8 PM12 AMfreezingfreezingvery coldvery coldcoldcool
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.

Nesbyen, Norway (3,966 miles away) is the far-away foreign place with temperatures most similar to Girdwood (view comparison).

Clouds

In Girdwood, 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 in Girdwood begins around February 16 and lasts for 2.4 months, ending around April 30. On March 16, the clearest day of the year, the sky is clear, mostly clear, or partly cloudy 41% of the time, and overcast or mostly cloudy 59% of the time.

The cloudier part of the year begins around April 30 and lasts for 9.6 months, ending around February 16. On December 18, the cloudiest day of the year, the sky is overcast or mostly cloudy 71% of the time, and clear, mostly clear, or partly cloudy 28% of the time.

Cloud Cover Categories

Cloud Cover Categories in GirdwoodclearercloudiercloudierJanFebMarAprMayJunJulAugSepOctNovDec0%100%10%90%20%80%30%70%40%60%50%50%60%40%70%30%80%20%90%10%100%0%Mar 1641%Mar 1641%Dec 1828%Dec 1828%Apr 3035%Apr 3035%clearpartly cloudymostly cloudyovercastmostly clear
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 in Girdwood varies throughout the year.

The wetter season lasts 6.2 months, from July 25 to February 3, with a greater than 45% chance of a given day being a wet day. The chance of a wet day peaks at 57% on September 24.

The drier season lasts 5.7 months, from February 3 to July 25. The smallest chance of a wet day is 34% on May 15.

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 Girdwood changes throughout the year.

Rain alone is the most common for 11 months, from January 3 to November 27. The highest chance of a day with rain alone is 57% on September 23.

Snow alone is the most common for 1.2 months, from November 27 to January 3. The highest chance of a day with snow alone is 21% on December 14.

Daily Chance of Precipitation

Daily Chance of Precipitation in GirdwoodrainsnowJanFebMarAprMayJunJulAugSepOctNovDec0%10%20%30%40%50%60%70%80%90%100%Sep 2457%Sep 2457%May 1534%May 1534%Jan 348%Jan 348%Nov 2748%Nov 2748%Jul 2545%Jul 2545%snowmixedrain
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. Girdwood experiences extreme seasonal variation in monthly rainfall.

Rain falls throughout the year in Girdwood. The most rain falls during the 31 days centered around September 20, with an average total accumulation of 7.0 inches.

The least rain falls around March 14, with an average total accumulation of 1.8 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. Girdwood experiences significant seasonal variation in monthly liquid-equivalent snowfall.

The snowy period of the year lasts for 7.2 months, from September 30 to May 3, with a sliding 31-day liquid-equivalent snowfall of at least 0.1 inches. The most snow falls during the 31 days centered around December 14, with an average total liquid-equivalent accumulation of 1.8 inches.

The snowless period of the year lasts for 4.9 months, from May 3 to September 30. The least snow falls around July 24, with an average total liquid-equivalent accumulation of 0.0 inches.

Average Liquid-Equivalent Monthly Snowfall

Average Liquid-Equivalent Monthly Snowfall in GirdwoodsnowsnowJanFebMarAprMayJunJulAugSepOctNovDec0 in1 in2 in3 in4 in5 in6 in7 inDec 141.8 inDec 141.8 inJul 240.0 inJul 240.0 inSep 300.1 inSep 300.1 inMay 30.1 inMay 30.1 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 Girdwood varies extremely over the course of the year. In 2017, the shortest day is December 21, with 5 hours, 33 minutes of daylight; the longest day is June 20, with 19 hours, 15 minutes of daylight.

Hours of Daylight and Twilight

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 4:20 AM on June 19, and the latest sunrise is 5 hours, 49 minutes later at 10:09 AM on December 26. The earliest sunset is at 3:40 PM on December 16, and the latest sunset is 7 hours, 56 minutes later at 11:36 PM on June 22.

Daylight saving time (DST) is observed in Girdwood 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 in GirdwoodJanFebMarAprMayJunJulAugSepOctNovDec2 AM4 AM6 AM8 AM10 AM12 PM2 PM4 PM6 PM8 PM10 PM12 AM2 AMJun 194:20 AMJun 194:20 AM11:36 PMJun 2211:36 PMJun 22Dec 163:40 PMDec 163:40 PM10:09 AMDec 2610:09 AMDec 26Mar 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.

The perceived humidity level in Girdwood, 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

Humidity Comfort Levels in GirdwoodJanFebMarAprMayJunJulAugSepOctNovDec0%10%20%30%40%50%60%70%80%90%100%Jul 30%Jul 30%drydry
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 in Girdwood experiences mild seasonal variation over the course of the year.

The windier part of the year lasts for 5.3 months, from November 6 to April 16, with average wind speeds of more than 6.5 miles per hour. The windiest day of the year is January 8, with an average hourly wind speed of 7.9 miles per hour.

The calmer time of year lasts for 6.7 months, from April 16 to November 6. The calmest day of the year is July 6, with an average hourly wind speed of 5.2 miles per hour.

Average Wind Speed

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 Girdwood is from the east throughout the year.

Wind Direction

Wind Direction in GirdwoodJanFebMarAprMayJunJulAugSepOctNovDec0%100%20%80%40%60%60%40%80%20%100%0%eastnorthwestsouth
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).

Water Temperature

Girdwood 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 water temperature experiences significant seasonal variation over the course of the year.

The time of year with warmer water lasts for 2.9 months, from June 25 to September 21, with an average temperature above 52°F. The day of the year with the warmest water is August 7, with an average temperature of 56°F.

The time of year with cooler water lasts for 5.4 months, from November 30 to May 12, with an average temperature below 39°F. The day of the year with the coolest water is March 2, with an average temperature of 34°F.

Average Water Temperature

The daily average water temperature (purple line), with 25th to 75th and 10th to 90th percentile bands.

Best Time of Year to Visit

To characterize how pleasant the weather is in Girdwood 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 Girdwood for general outdoor tourist activities is from early July to early August, with a peak score in the third week of July.

Tourism Score

Tourism Score in GirdwoodJanFebMarAprMayJunJulAugSepOctNovDec02468102.62.60.00.0 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 Girdwood for hot-weather activities is from early to mid July.

Beach/Pool Score

Beach/Pool Score in GirdwoodJanFebMarAprMayJunJulAugSepOctNovDec02468100.10.10.00.0precipitationprecipitationcloudscloudstemperaturetemperature
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 Girdwood typically lasts for 4.5 months (138 days), from around May 9 to around September 24, rarely starting before April 21 or after May 27, and rarely ending before September 7 or after October 11.

Time Spent in Various Temperature Bands and the Growing Season

Time Spent in Various Temperature Bands and the Growing Season in Girdwoodgrowing seasonJanFebMarAprMayJunJulAugSepOctNovDec0%100%10%90%20%80%30%70%40%60%50%50%60%40%70%30%80%20%90%10%100%0%May 950%May 950%Sep 2450%Sep 2450%May 2790%May 2790%Sep 790%Sep 790%Apr 2110%Apr 2110%Oct 1110%Oct 1110%0%Feb 160%Feb 16Jul 20100%Jul 20100%frigidfreezingvery coldcoldcool
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 in Girdwood should appear around June 11, only rarely appearing before May 31 or after June 26.

Growing Degree Days

Growing Degree Days in GirdwoodJanFebMarAprMayJunJulAugSepOctNovDec0°F100°F200°F300°F400°F500°F600°F700°FJun 1190°FJun 1190°FDec 31608°FDec 31608°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 extreme seasonal variation over the course of the year.

The brighter period of the year lasts for 2.9 months, from April 27 to July 25, with an average daily incident shortwave energy per square meter above 4.5 kWh. The brightest day of the year is June 9, with an average of 5.6 kWh.

The darker period of the year lasts for 4.1 months, from October 17 to February 21, with an average daily incident shortwave energy per square meter below 1.2 kWh. The darkest day of the year is December 21, with an average of 0.1 kWh.

Average Daily Incident Shortwave Solar Energy

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 Girdwood are 60.943 deg latitude, -149.166 deg longitude, and 223 ft elevation.

The topography within 2 miles of Girdwood contains extreme variations in elevation, with a maximum elevation change of 3,435 feet and an average elevation above sea level of 473 feet. Within 10 miles also contains extreme variations in elevation (6,542 feet). Within 50 miles also contains extreme variations in elevation (10,561 feet).

The area within 2 miles of Girdwood is covered by trees (39%), water (34%), and shrubs (11%), within 10 miles by shrubs (30%) and trees (19%), and within 50 miles by shrubs (22%) and trees (21%).

Data Sources

This report illustrates the typical weather in Girdwood, 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 2 weather stations near enough to contribute to our estimation of the temperature and dew point in Girdwood.

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

The stations contributing to this reconstruction are: Portage, Portage Glacier (70%, 25 kilometers, southeast) and Bryant Army Heliport (30%, 45 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 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.