Average Weather in June at Seattle-Tacoma International Airport Washington, United States
Daily high temperatures increase by 6°F, from 68°F to 74°F, rarely falling below 59°F or exceeding 84°F.
Daily low temperatures increase by 4°F, from 51°F to 55°F, rarely falling below 47°F or exceeding 60°F.
For reference, on August 3, the hottest day of the year, temperatures at Seattle-Tacoma International Airport typically range from 58°F to 78°F, while on December 23, the coldest day of the year, they range from 37°F to 45°F.
Average High and Low Temperature in June
The figure below shows you a compact characterization of the hourly average temperatures for the quarter of the year centered on June. 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.
Average Hourly Temperature in June
The month of June at Seattle-Tacoma International Airport experiences rapidly decreasing cloud cover, with the percentage of time that the sky is overcast or mostly cloudy decreasing from 54% to 40%.
The clearest day of the month is June 30, with clear, mostly clear, or partly cloudy conditions 60% of the time.
For reference, on January 19, the cloudiest day of the year, the chance of overcast or mostly cloudy conditions is 73%, while on August 3, the clearest day of the year, the chance of clear, mostly clear, or partly cloudy skies is 75%.
Cloud Cover Categories in June
A wet day is one with at least 0.04 inches of liquid or liquid-equivalent precipitation. At Seattle-Tacoma International Airport, the chance of a wet day over the course of June is very rapidly decreasing, starting the month at 29% and ending it at 18%.
For reference, the year's highest daily chance of a wet day is 57% on November 18, and its lowest chance is 8% on August 11.
Probability of Precipitation in June
To 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 June at Seattle-Tacoma International Airport is decreasing, starting the month at 2.0 inches, when it rarely exceeds 3.4 inches or falls below 0.6 inches, and ending the month at 1.2 inches, when it rarely exceeds 2.2 inches or falls below 0.2 inches.
Average Monthly Rainfall in June
Over the course of June at Seattle-Tacoma International Airport, the length of the day is essentially constant. The shortest day of the month is June 1, with 15 hours, 42 minutes of daylight and the longest day is June 21, with 15 hours, 58 minutes of daylight.
Hours of Daylight and Twilight in June
The latest sunrise of the month at Seattle-Tacoma International Airport is 5:16 AM on June 1 and the earliest sunrise is 5 minutes earlier at 5:11 AM on June 16.
The earliest sunset is 8:58 PM on June 1 and the latest sunset is 12 minutes later at 9:10 PM on June 25.
Daylight saving time is observed at Seattle-Tacoma International Airport during 2018, but it neither starts nor ends during June, so the entire month is in daylight saving time.
For reference, on June 21, the longest day of the year, the Sun rises at 5:12 AM and sets 15 hours, 58 minutes later, at 9:10 PM, while on December 21, the shortest day of the year, it rises at 7:54 AM and sets 8 hours, 27 minutes later, at 4:20 PM.
Sunrise & Sunset with Twilight in June
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 chance that a given day will be muggy at Seattle-Tacoma International Airport is essentially constant during June, remaining around 0% throughout.
For reference, on August 4, 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.
Humidity Comfort Levels in June
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 Seattle-Tacoma International Airport is essentially constant during June, remaining within 0.2 miles per hour of 3.4 miles per hour throughout.
For reference, on December 1, the windiest day of the year, the daily average wind speed is 5.4 miles per hour, while on August 2, the calmest day of the year, the daily average wind speed is 3.0 miles per hour.
Average Wind Speed in June
Wind Direction in June
Seattle-Tacoma International 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 surface water temperature at Seattle-Tacoma International Airport is gradually increasing during June, rising by 2°F, from 53°F to 55°F, over the course of the month.
Average Water Temperature in June
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 at Seattle-Tacoma International Airport typically lasts for 9.2 months (279 days), from around February 22 to around November 28, rarely starting before January 23 or after March 17, and rarely ending before November 4 or after December 21.
The month of June at Seattle-Tacoma International Airport is reliably fully within the growing season.
Time Spent in Various Temperature Bands and the Growing Season in June
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 Seattle-Tacoma International Airport are increasing during June, increasing by 301°F, from 338°F to 639°F, over the course of the month.
Growing Degree Days in June
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 at Seattle-Tacoma International Airport is gradually increasing during June, rising by 0.7 kWh, from 5.9 kWh to 6.5 kWh, over the course of the month.
Average Daily Incident Shortwave Solar Energy in June
For the purposes of this report, the geographical coordinates of Seattle-Tacoma International Airport are 47.449 deg latitude, -122.309 deg longitude, and 302 ft elevation.
The topography within 2 miles of Seattle-Tacoma International Airport contains only modest variations in elevation, with a maximum elevation change of 469 feet and an average elevation above sea level of 341 feet. Within 10 miles contains only modest variations in elevation (1,109 feet). Within 50 miles contains very significant variations in elevation (14,360 feet).
The area within 2 miles of Seattle-Tacoma International Airport is covered by artificial surfaces (99%), within 10 miles by artificial surfaces (55%) and water (28%), and within 50 miles by trees (53%) and artificial surfaces (14%).
This report illustrates the typical weather at Seattle-Tacoma International Airport year round, 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
Seattle-Tacoma International 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 King County International Airport, Renton Municipal Airport, Tacoma Narrows Airport, McChord Field Airport (Joint Base Lewis-McChord), Pierce County Airport Thun Field, Madigan Hospital Heliport, Bremerton National Airport, and Snohomish County Airport (Paine Field).
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.
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.