Average Weather in Chelan Washington, United States
In Chelan, the summers are warm, dry, and mostly clear and the winters are freezing, snowy, and partly cloudy. Over the course of the year, the temperature typically varies from 21°F to 88°F and is rarely below 8°F or above 97°F.
The hot season lasts for 3.1 months, from June 12 to September 14, with an average daily high temperature above 76°F. The hottest day of the year is August 2, with an average high of 88°F and low of 60°F.
The cold season lasts for 3.2 months, from November 16 to February 23, with an average daily high temperature below 42°F. The coldest day of the year is December 30, with an average low of 21°F and high of 30°F.
Average High and Low Temperature
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
In Chelan, 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 in Chelan begins around June 8 and lasts for 4.0 months, ending around October 7. On August 3, the clearest day of the year, the sky is clear, mostly clear, or partly cloudy 80% of the time, and overcast or mostly cloudy 20% of the time.
The cloudier part of the year begins around October 7 and lasts for 8.0 months, ending around June 8. On January 15, the cloudiest day of the year, the sky is overcast or mostly cloudy 67% of the time, and clear, mostly clear, or partly cloudy 33% of the time.
A wet day is one with at least 0.04 inches of liquid or liquid-equivalent precipitation. The chance of wet days in Chelan varies throughout the year.
The wetter season lasts 5.2 months, from October 20 to March 27, with a greater than 18% chance of a given day being a wet day. The chance of a wet day peaks at 32% on December 1.
The drier season lasts 6.8 months, from March 27 to October 20. The smallest chance of a wet day is 5% on August 16.
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 Chelan changes throughout the year.
Rain alone is the most common for 10 months, from January 30 to December 4. The highest chance of a day with rain alone is 24% on November 9.
Snow alone is the most common for 1.9 months, from December 4 to January 30. The highest chance of a day with snow alone is 19% on December 29.
Daily Chance of Precipitation
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. Chelan experiences some seasonal variation in monthly rainfall.
The rainy period of the year lasts for 9.1 months, from September 22 to June 25, with a sliding 31-day rainfall of at least 0.5 inches. The most rain falls during the 31 days centered around November 12, with an average total accumulation of 1.6 inches.
The rainless period of the year lasts for 2.9 months, from June 25 to September 22. The least rain falls around August 16, with an average total accumulation of 0.3 inches.
Average Monthly Rainfall
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. Chelan experiences significant seasonal variation in monthly liquid-equivalent snowfall.
The snowy period of the year lasts for 4.7 months, from October 28 to March 18, 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 27, with an average total liquid-equivalent accumulation of 1.2 inches.
The snowless period of the year lasts for 7.3 months, from March 18 to October 28. The least snow falls around July 11, with an average total liquid-equivalent accumulation of 0.0 inches.
Average Liquid-Equivalent Monthly Snowfall
The length of the day in Chelan varies extremely over the course of the year. In 2017, the shortest day is December 21, with 8 hours, 24 minutes of daylight; the longest day is June 21, with 16 hours, 1 minute of daylight.
Hours of Daylight and Twilight
The earliest sunrise is at 5:00 AM on June 16, and the latest sunrise is 2 hours, 49 minutes later at 7:49 AM on November 4. The earliest sunset is at 4:07 PM on December 10, and the latest sunset is 4 hours, 56 minutes later at 9:03 PM on June 25.
Daylight saving time (DST) is observed in Chelan 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
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 Chelan, 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
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 Chelan does not vary significantly over the course of the year, remaining within 0.4 miles per hour of 2.7 miles per hour throughout.
Average Wind Speed
The predominant average hourly wind direction in Chelan varies throughout the year.
The wind is most often from the west for 8.7 months, from February 28 to November 19, with a peak percentage of 63% on June 23. The wind is most often from the north for 3.3 months, from November 19 to February 28, with a peak percentage of 46% on January 1.
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 3.3 months, from May 13 to August 21, with an average daily incident shortwave energy per square meter above 6.3 kWh. The brightest day of the year is July 14, with an average of 7.6 kWh.
The darker period of the year lasts for 3.7 months, from October 25 to February 16, with an average daily incident shortwave energy per square meter below 2.4 kWh. The darkest day of the year is December 24, with an average of 1.1 kWh.
Average Daily Incident Shortwave Solar Energy
For the purposes of this report, the geographical coordinates of Chelan are 47.841 deg latitude, -120.016 deg longitude, and 1,640 ft elevation.
The topography within 2 miles of Chelan contains large variations in elevation, with a maximum elevation change of 2,310 feet and an average elevation above sea level of 1,553 feet. Within 10 miles contains large variations in elevation (4,416 feet). Within 50 miles also contains extreme variations in elevation (8,799 feet).
The area within 2 miles of Chelan is covered by grassland (45%) and shrubs (36%), within 10 miles by shrubs (42%) and grassland (23%), and within 50 miles by shrubs (47%) and trees (18%).
This report illustrates the typical weather in Chelan, 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 4 weather stations near enough to contribute to our estimation of the temperature and dew point in Chelan.
For each station, the records are corrected for the elevation difference between that station and Chelan 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 Chelan is computed as the weighted average of the individual contributions from each station, with weights proportional to the inverse of the distance between Chelan and a given station.
The stations contributing to this reconstruction are: Pangborn Field (43%, 51 kilometers, south); Ephrata Municipal Airport (27%, 70 kilometers, southeast); Omak Airport (23%, 79 kilometers, northeast); and Arlington Municipal Airport (7%, 164 kilometers, west).
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.