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Average Weather in October in Sunnyside Washington, United States

In Sunnyside, the month of October is characterized by very rapidly falling daily high temperatures, with daily highs decreasing by 17°F, from 74°F to 57°F over the course of the month, and rarely exceeding 84°F or dropping below 49°F.

Daily low temperatures decrease by 9°F, from 46°F to 37°F, rarely falling below 26°F or exceeding 55°F.

For reference, on July 30, the hottest day of the year, temperatures in Sunnyside typically range from 62°F to 94°F, while on December 23, the coldest day of the year, they range from 26°F to 37°F.

Average High and Low Temperature in October

The daily average high (red line) and low (blue line) temperature, with 25th to 75th and 10th to 90th percentile bands. The thin dotted lines are the corresponding average perceived temperatures.

The figure below shows you a compact characterization of the hourly average temperatures for the quarter of the year centered on October. 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 October

Average Hourly Temperature in October in Sunnyside18152229112233445566778899101011111212131314141515161617171818191920202121222223232424252526262727282829293030313112 AM4 AM8 AM12 PM4 PM8 PM12 AMSepNovvery coldwarmcoldcoolcomfortablefreezing
The average hourly temperature, color coded into bands: frigid < 15°F < freezing < 32°F < very cold < 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.


The month of October in Sunnyside experiences very rapidly increasing cloud cover, with the percentage of time that the sky is overcast or mostly cloudy increasing from 37% to 54%.

The clearest day of the month is October 1, with clear, mostly clear, or partly cloudy conditions 63% of the time.

For reference, on January 16, the cloudiest day of the year, the chance of overcast or mostly cloudy conditions is 65%, while on August 4, the clearest day of the year, the chance of clear, mostly clear, or partly cloudy skies is 83%.

Cloud Cover Categories in October

Cloud Cover Categories in October in Sunnyside1815222911223344556677889910101111121213131414151516161717181819192020212122222323242425252626272728282929303031310%100%10%90%20%80%30%70%40%60%50%50%60%40%70%30%80%20%90%10%100%0%SepNovOct 163%Oct 163%Oct 3146%Oct 3146%Oct 1157%Oct 1157%Oct 2151%Oct 2151%clearovercastmostly clearpartly cloudymostly cloudy
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.


A wet day is one with at least 0.04 inches of liquid or liquid-equivalent precipitation. In Sunnyside, the chance of a wet day over the course of October is very rapidly increasing, starting the month at 7% and ending it at 16%.

For reference, the year's highest daily chance of a wet day is 23% on December 1, and its lowest chance is 2% on August 16.

Probability of Precipitation in October

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).


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 October in Sunnyside is gradually increasing, starting the month at 0.4 inches, when it rarely exceeds 0.8 inches, and ending the month at 0.8 inches, when it rarely exceeds 1.5 inches or falls below 0.1 inches.

Average Monthly Rainfall in October

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.


Over the course of October in Sunnyside, the length of the day is rapidly decreasing. From the start to the end of the month, the length of the day decreases by 1 hour, 34 minutes, implying an average daily decrease of 3 minutes, 9 seconds, and weekly decrease of 21 minutes, 60 seconds.

The shortest day of the month is October 31, with 10 hours, 6 minutes of daylight and the longest day is October 1, with 11 hours, 40 minutes of daylight.

Hours of Daylight and Twilight in October

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 of the month in Sunnyside is 6:59 AM on October 1 and the latest sunrise is 41 minutes later at 7:40 AM on October 31.

The latest sunset is 6:39 PM on October 1 and the earliest sunset is 53 minutes earlier at 5:46 PM on October 31.

Daylight saving time is observed in Sunnyside during 2017, but it neither starts nor ends during October, so the entire month is in daylight saving time.

For reference, on June 21, the longest day of the year, the Sun rises at 5:07 AM and sets 15 hours, 48 minutes later, at 8:55 PM, while on December 21, the shortest day of the year, it rises at 7:40 AM and sets 8 hours, 36 minutes later, at 4:16 PM.

Sunrise & Sunset with Twilight and Daylight Saving Time in October

Sunrise & Sunset with Twilight and Daylight Saving Time in October in Sunnyside18152229112233445566778899101011111212131314141515161617171818191920202121222223232424252526262727282829293030313112 AM2 AM4 AM6 AM8 AM10 AM12 PM2 PM4 PM6 PM8 PM10 PM12 AMSepNov6:59 AM6:59 AMOct 16:39 PMOct 16:39 PM7:40 AM7:40 AMOct 315:46 PMOct 315:46 PM7:12 AM7:12 AMOct 116:20 PMOct 116:20 PM7:26 AM7:26 AMOct 216:02 PMOct 216:02 PMSolarMidnightSolarMidnightSolarNoonSunriseSunset
The solar day over the course of October. 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.


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 in Sunnyside is essentially constant during October, remaining around 0% throughout.

For reference, on July 15, 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 October

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.


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 Sunnyside is essentially constant during October, remaining within 0.2 miles per hour of 7.5 miles per hour throughout.

For reference, on March 31, the windiest day of the year, the daily average wind speed is 8.7 miles per hour, while on September 9, the calmest day of the year, the daily average wind speed is 7.3 miles per hour.

Average Wind Speed in October

The average of mean hourly wind speeds (dark gray line), with 25th to 75th and 10th to 90th percentile bands.
The hourly average wind direction in Sunnyside throughout October is predominantly from the west, with a peak proportion of 47% on October 1.

Wind Direction in October

Wind Direction in October in SunnysideWN1815222911223344556677889910101111121213131414151516161717181819192020212122222323242425252626272728282929303031310%100%10%90%20%80%30%70%40%60%50%50%60%40%70%30%80%20%90%10%100%0%SepNovwestnorthsoutheast
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).

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 in Sunnyside is rapidly decreasing during October, falling by 1.8 kWh, from 4.1 kWh to 2.4 kWh, over the course of the month.

Average Daily Incident Shortwave Solar Energy in October

The average daily shortwave solar energy reaching the ground per square meter (orange line), with 25th to 75th and 10th to 90th percentile bands.


For the purposes of this report, the geographical coordinates of Sunnyside are 46.324 deg latitude, -120.009 deg longitude, and 778 ft elevation.

The topography within 2 miles of Sunnyside contains only modest variations in elevation, with a maximum elevation change of 308 feet and an average elevation above sea level of 768 feet. Within 10 miles contains only modest variations in elevation (2,116 feet). Within 50 miles contains large variations in elevation (5,597 feet).

The area within 2 miles of Sunnyside is covered by cropland (55%) and artificial surfaces (45%), within 10 miles by cropland (61%) and shrubs (25%), and within 50 miles by shrubs (60%) and cropland (27%).

Data Sources

This report illustrates the typical weather in Sunnyside 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

There are 4 weather stations near enough to contribute to our estimation of the temperature and dew point in Sunnyside.

For each station, the records are corrected for the elevation difference between that station and Sunnyside 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 Sunnyside is computed as the weighted average of the individual contributions from each station, with weights proportional to the inverse of the distance between Sunnyside and a given station.

The stations contributing to this reconstruction are: Hanford (43%, 41 kilometers, northeast); Yakima Air Terminal Airport (32%, 49 kilometers, northwest); Hermiston Municipal Airport (16%, 80 kilometers, southeast); and The Dalles Municipal Airport (9%, 119 kilometers, southwest).

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.


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.