Average Weather at Friday Harbor Airport Washington, United States

At Friday Harbor Airport, the summers are comfortable, dry, and partly cloudy and the winters are long, chilly, wet, and mostly cloudy. Over the course of the year, the temperature typically varies from 36°F to 73°F and is rarely below 26°F or above 82°F.

The warm season lasts for 3.0 months, from June 15 to September 15, with an average daily high temperature above 67°F. The hottest day of the year is August 1, with an average high of 73°F and low of 51°F.

The cool season lasts for 3.8 months, from November 12 to March 7, with an average daily high temperature below 50°F. The coldest day of the year is January 2, with an average low of 36°F and high of 45°F.

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

The average hourly temperature, color coded into bands: frigid < 15°F < freezing < 32°F < chilly < 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.

Clouds

At Friday Harbor Airport, the average percentage of the sky covered by clouds experiences significant seasonal variation over the course of the year.

The clearer part of the year at Friday Harbor Airport begins around June 7 and lasts for 3.9 months, ending around October 3. On August 3, the clearest day of the year, the sky is clear, mostly clear, or partly cloudy 74% of the time, and overcast or mostly cloudy 26% of the time.

The cloudier part of the year begins around October 3 and lasts for 8.1 months, ending around June 7. On January 19, the cloudiest day of the year, the sky is overcast or mostly cloudy 69% of the time, and clear, mostly clear, or partly cloudy 31% of the time.

Cloud Cover

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 Friday Harbor Airport varies significantly throughout the year.

The wetter season lasts 6.2 months, from October 11 to April 18, with a greater than 31% chance of a given day being a wet day. The chance of a wet day peaks at 55% on November 18.

The drier season lasts 5.8 months, from April 18 to October 11. The smallest chance of a wet day is 7% on August 9.

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 54% on November 18.

Daily Chance of Precipitation

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. Friday Harbor Airport experiences extreme seasonal variation in monthly rainfall.

Rain falls throughout the year at Friday Harbor Airport. The most rain falls during the 31 days centered around November 20, with an average total accumulation of 5.7 inches.

The least rain falls around July 30, with an average total accumulation of 0.6 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

The sliding 31-day liquid-equivalent quantity of snowfall at Friday Harbor Airport does not vary significantly over the course of the year, staying within 0.1 inches of 0.1 inches throughout.

Average Liquid-Equivalent Monthly Snowfall

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 Friday Harbor Airport varies extremely over the course of the year. In 2017, the shortest day is December 21, with 8 hours, 18 minutes of daylight; the longest day is June 21, with 16 hours, 8 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 5:09 AM on June 16, and the latest sunrise is 2 hours, 55 minutes later at 8:04 AM on January 1. The earliest sunset is at 4:16 PM on December 11, and the latest sunset is 5 hours, 2 minutes later at 9:18 PM on June 25.

Daylight saving time (DST) is observed at Friday Harbor 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

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 at Friday Harbor Airport, 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

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 Friday Harbor Airport experiences mild seasonal variation over the course of the year.

The windier part of the year lasts for 5.2 months, from October 26 to April 1, with average wind speeds of more than 3.6 miles per hour. The windiest day of the year is December 4, with an average hourly wind speed of 4.8 miles per hour.

The calmer time of year lasts for 6.8 months, from April 1 to October 26. The calmest day of the year is September 9, with an average hourly wind speed of 2.5 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 at Friday Harbor Airport varies throughout the year.

The wind is most often from the west for 6.5 months, from March 26 to October 9, with a peak percentage of 75% on July 18. The wind is most often from the east for 5.5 months, from October 9 to March 26, with a peak percentage of 52% on January 1.

Wind Direction

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

Friday Harbor Airport 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 some seasonal variation over the course of the year.

The time of year with warmer water lasts for 3.0 months, from June 19 to September 19, with an average temperature above 53°F. The day of the year with the warmest water is August 3, with an average temperature of 56°F.

The time of year with cooler water lasts for 4.2 months, from December 1 to April 7, with an average temperature below 48°F. The day of the year with the coolest water is January 29, with an average temperature of 46°F.

Average Water Temperature

The daily average water temperature (purple line), 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 3.4 months, from May 10 to August 21, with an average daily incident shortwave energy per square meter above 5.7 kWh. The brightest day of the year is July 16, with an average of 6.9 kWh.

The darker period of the year lasts for 3.9 months, from October 23 to February 20, with an average daily incident shortwave energy per square meter below 2.1 kWh. The darkest day of the year is December 25, with an average of 0.9 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 Friday Harbor Airport are 48.526 deg latitude, -123.025 deg longitude, and 66 ft elevation.

The topography within 2 miles of Friday Harbor Airport contains only modest variations in elevation, with a maximum elevation change of 318 feet and an average elevation above sea level of 89 feet. Within 10 miles contains only modest variations in elevation (1,496 feet). Within 50 miles contains very significant variations in elevation (7,608 feet).

The area within 2 miles of Friday Harbor Airport is covered by cropland (32%), water (26%), artificial surfaces (18%), and trees (16%), within 10 miles by water (62%) and trees (25%), and within 50 miles by water (41%) and trees (35%).

Data Sources

This report illustrates the typical weather at Friday Harbor 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

Friday Harbor 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 Orcas Island Airport, Discovery Island, Saturna Island Meteorological Aeronautical Presentation System, Saturna / Capmon, Victoria University, Victoria Automatic Weather Reporting System, Victoria Harbour, and Naval Air Station Whidbey Island.

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.