Average Weather in Dayton Washington, United States
In Dayton, the summers are short, hot, dry, and mostly clear and the winters are very cold and mostly cloudy. Over the course of the year, the temperature typically varies from 28°F to 89°F and is rarely below 15°F or above 98°F.
The hot season lasts for 2.7 months, from June 21 to September 10, with an average daily high temperature above 79°F. The hottest day of the year is August 2, with an average high of 89°F and low of 60°F.
The cold season lasts for 3.3 months, from November 13 to February 22, with an average daily high temperature below 47°F. The coldest day of the year is December 23, with an average low of 28°F and high of 36°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 Dayton, 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 Dayton begins around June 11 and lasts for 3.9 months, ending around October 8. On July 29, the clearest day of the year, the sky is clear, mostly clear, or partly cloudy 82% of the time, and overcast or mostly cloudy 18% of the time.
The cloudier part of the year begins around October 8 and lasts for 8.1 months, ending around June 11. On January 15, the cloudiest day of the year, the sky is overcast or mostly cloudy 68% of the time, and clear, mostly clear, or partly cloudy 32% of the time.
Cloud Cover Categories
A wet day is one with at least 0.04 inches of liquid or liquid-equivalent precipitation. The chance of wet days in Dayton varies throughout the year.
The wetter season lasts 7.4 months, from October 20 to June 1, with a greater than 21% chance of a given day being a wet day. The chance of a wet day peaks at 36% on November 28.
The drier season lasts 4.6 months, from June 1 to October 20. The smallest chance of a wet day is 7% on August 2.
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 31% 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 of the year. Dayton experiences some seasonal variation in monthly rainfall.
The rainy period of the year lasts for 10 months, from September 4 to July 11, 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 1.9 inches.
The rainless period of the year lasts for 1.8 months, from July 11 to September 4. The least rain falls around August 1, with an 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 of the year. Dayton experiences some seasonal variation in monthly liquid-equivalent snowfall.
The snowy period of the year lasts for 3.5 months, from November 15 to February 28, 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 0.4 inches.
The snowless period of the year lasts for 8.6 months, from February 28 to November 15. The least snow falls around July 19, with an average total liquid-equivalent accumulation of 0.0 inches.
Average Liquid-Equivalent Monthly Snowfall
The length of the day in Dayton varies significantly over the course of the year. In 2017, the shortest day is December 21, with 8 hours, 36 minutes of daylight; the longest day is June 20, with 15 hours, 48 minutes of daylight.
Hours of Daylight and Twilight
The earliest sunrise is at 4:59 AM on June 15, and the latest sunrise is 2 hours, 39 minutes later at 7:38 AM on November 4. The earliest sunset is at 4:05 PM on December 10, and the latest sunset is 4 hours, 43 minutes later at 8:48 PM on June 25.
Daylight saving time (DST) is observed in Dayton 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 Dayton, 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 Dayton experiences mild seasonal variation over the course of the year.
The windier part of the year lasts for 5.8 months, from October 28 to April 20, with average wind speeds of more than 7.9 miles per hour. The windiest day of the year is November 19, with an average hourly wind speed of 8.8 miles per hour.
The calmer time of year lasts for 6.2 months, from April 20 to October 28. The calmest day of the year is August 12, with an average hourly wind speed of 7.1 miles per hour.
Average Wind Speed
The predominant average hourly wind direction in Dayton varies throughout the year.
The wind is most often from the west for 6.5 months, from March 19 to October 5, with a peak percentage of 57% on June 23. The wind is most often from the south for 5.5 months, from October 5 to March 19, with a peak percentage of 63% 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 3.1 months, from May 19 to August 22, with an average daily incident shortwave energy per square meter above 6.4 kWh. The brightest day of the year is July 13, with an average of 7.7 kWh.
The darker period of the year lasts for 3.7 months, from October 27 to February 19, with an average daily incident shortwave energy per square meter below 2.5 kWh. The darkest day of the year is December 23, with an average of 1.2 kWh.
Average Daily Incident Shortwave Solar Energy
For the purposes of this report, the geographical coordinates of Dayton are 46.324 deg latitude, -117.972 deg longitude, and 2,011 ft elevation.
The topography within 2 miles of Dayton contains significant variations in elevation, with a maximum elevation change of 764 feet and an average elevation above sea level of 1,889 feet. Within 10 miles contains significant variations in elevation (3,041 feet). Within 50 miles contains large variations in elevation (6,024 feet).
The area within 2 miles of Dayton is covered by cropland (93%), within 10 miles by cropland (66%) and shrubs (17%), and within 50 miles by shrubs (35%) and cropland (32%).
This report illustrates the typical weather in Dayton, 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 3 weather stations near enough to contribute to our estimation of the temperature and dew point in Dayton.
For each station, the records are corrected for the elevation difference between that station and Dayton 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 Dayton is computed as the weighted average of the individual contributions from each station, with weights proportional to the inverse of the distance between Dayton and a given station.
The stations contributing to this reconstruction are: Walla Walla Regional Airport (55%, 35 kilometers, southwest); Lewiston–Nez Perce County Airport (24%, 74 kilometers, east); and Pullman–Moscow Regional Airport (21%, 81 kilometers, northeast).
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.