Average Weather in Spokane Washington, United States
Spokane has a continental climate with dry warm summers. The temperature typically varies from 26°F to 88°F over the course of the year, and is rarely below 11°F or above 97°F.
The hot season lasts for 86 days, from June 18 to September 12, with an average daily high temperature above 77°F. The hottest day of the year is August 2, with an average high of 88°F and low of 59°F.
The cold season lasts for 103 days, from November 13 to February 24, with an average daily high temperature below 45°F. The coldest day of the year is December 30, with an average low of 26°F and high of 34°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
The length of the day in Spokane varies significantly over the course of the year. In 2017, the shortest day is December 21, with 8 hours, 25 minutes of daylight; the longest day is June 21, with 15 hours, 60 minutes of daylight.
Hours of Daylight and Twilight
The earliest sunrise is at 4:51 AM on June 16, and the latest sunrise is 2 hours, 48 minutes later at 7:39 AM on November 4. The earliest sunset is at 3:57 PM on December 10, and the latest sunset is 4 hours, 54 minutes later at 8:51 PM on June 25.
Daylight saving time (DST) is observed in Spokane during 2017, starting in the spring on March 12, lasting 237 days, and ending in the fall on November 5.
Sunrise & Sunset with Twilight and Daylight Saving Time
In Spokane, the average percentage of the sky covered by clouds experiences extreme seasonal variation over the course of the year.
The clearer part of the year in Spokane begins around June 6 and lasts for 127 days, ending around October 11. On July 29, the clearest day of the year, the sky is clear, mostly clear, or partly cloudy 79% of the time, and overcast or mostly cloudy 21% of the time.
The cloudier part of the year begins around October 11 and lasts for 238 days, ending around June 6. On January 10, the cloudiest day of the year, the sky is overcast or mostly cloudy 74% of the time, and clear, mostly clear, or partly cloudy 26% 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 Spokane varies significantly throughout the year.
The wetter season lasts 228 days, from October 21 to June 6, with a greater than 23% chance of a given day being a wet day. The chance of a wet day peaks at 37% on November 28.
The drier season lasts 137 days, from June 6 to October 21. The smallest chance of a wet day is 7% on August 4.
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 33% on November 10.
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 in the year. Spokane experiences some seasonal variation in monthly rainfall.
The rainy period of the year lasts for 332 days, from August 27 to July 25, with a sliding 31-day rainfall of at least 0.5 inches. The most rain falls during the 31 days centered around November 20, with an average total accumulation of 2.4 inches.
The rainless period of the year lasts for 33 days, from July 25 to August 27. The least rain falls around August 9, with and average total accumulation of 0.4 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 in the year. Spokane experiences some seasonal variation in monthly liquid-equivalent snowfall.
The snowy period of the year lasts for 114 days, from November 14 to March 8, 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 31, with an average total liquid-equivalent accumulation of 0.5 inches.
The snowless period of the year lasts for 251 days, from March 8 to November 14. The least snow falls around July 17, with an average total liquid-equivalent accumulation of 0.0 inches.
Average Liquid-Equivalent Monthly Snowfall
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 Spokane, 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 Spokane does not vary significantly over the course of the year, remaining within 0.3 miles per hour of 3.4 miles per hour throughout.
Average Wind Speed
The predominant average hourly wind direction in Spokane varies throughout the year.
The wind is most often from the west for 34 days, from April 20 to May 24 and for 102 days, from June 19 to September 29, with a peak percentage of 42% on August 29. The wind is most often from the south for 26 days, from May 24 to June 19 and for 203 days, from September 29 to April 20, with a peak percentage of 47% on November 17.
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 very significant seasonal variation over the course of the year.
The brighter period of the year lasts for 98 days, from May 16 to August 22, with an average daily incident shortwave energy per square meter above 6.2 kWh. The brightest day of the year is July 15, with an average of 7.6 kWh.
The darker period of the year lasts for 118 days, from October 25 to February 20, with an average daily incident shortwave energy per square meter below 2.4 kWh. The darkest day of the year is December 26, with an average of 1.0 kWh.
Average Daily Incident Shortwave Solar Energy
The area within 2 miles of Spokane is covered by shrubs (51%), artificial surfaces (39%), and trees (10%), within 10 miles by shrubs (55%) and artificial surfaces (19%), and within 50 miles by shrubs (32%) and cropland (26%).
The topography within 2 miles of Spokane contains significant variations in elevation, with a maximum elevation change of 597 feet, and an average elevation above sea level of 1,925 feet. Within 10 miles contains large variations in elevation (2,136 feet). Within 50 miles contains extreme variations in elevation (4,570 feet).
This report illustrates the typical weather in Spokane, 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 Spokane.
For each station, the records are are corrected for the elevation difference between that station and Spokane 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 Spokane is computed as the weighted average of the individual contributions from each station, with weights proportional to the inverse of the distance between Spokane and a given station.
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 .