Average Weather in May in Umatilla Oregon, United States
Daily high temperatures increase by 8°F, from 71°F to 79°F, rarely falling below 62°F or exceeding 91°F.
Daily low temperatures increase by 8°F, from 45°F to 52°F, rarely falling below 36°F or exceeding 60°F.
For reference, on July 30, the hottest day of the year, temperatures in Umatilla typically range from 61°F to 93°F, while on December 30, the coldest day of the year, they range from 27°F to 39°F.
Average High and Low Temperature in May
The figure below shows you a compact characterization of the hourly average temperatures for the quarter of the year centered on May. 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 May
The month of May in Umatilla experiences essentially constant cloud cover, with the percentage of time that the sky is overcast or mostly cloudy remaining about 48% throughout the month.
The clearest day of the month is May 31, with clear, mostly clear, or partly cloudy conditions 54% 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 July 29, the clearest day of the year, the chance of clear, mostly clear, or partly cloudy skies is 82%.
Cloud Cover Categories in May
A wet day is one with at least 0.04 inches of liquid or liquid-equivalent precipitation. In Umatilla, the chance of a wet day over the course of May is gradually increasing, starting the month at 12% and ending it at 14%.
For reference, the year's highest daily chance of a wet day is 23% on November 29, and its lowest chance is 3% on August 4.
Probability of Precipitation in May
The average sliding 31-day rainfall during May in Umatilla is essentially constant, remaining about 0.7 inches throughout, and rarely exceeding 1.5 inches or falling below 0.2 inches.
The highest average 31-day accumulation is 0.8 inches on May 21.
Average Monthly Rainfall in May
Over the course of May in Umatilla, the length of the day is rapidly increasing. From the start to the end of the month, the length of the day increases by 1 hour, 8 minutes, implying an average daily increase of 2 minutes, 15 seconds, and weekly increase of 15 minutes, 47 seconds.
The shortest day of the month is May 1, with 14 hours, 21 minutes of daylight and the longest day is May 31, with 15 hours, 29 minutes of daylight.
Hours of Daylight and Twilight in May
The latest sunrise of the month in Umatilla is 5:44 AM on May 1 and the earliest sunrise is 33 minutes earlier at 5:10 AM on May 31.
The earliest sunset is 8:05 PM on May 1 and the latest sunset is 34 minutes later at 8:39 PM on May 31.
Daylight saving time is observed in Umatilla during 2018, but it neither starts nor ends during May, so the entire month is in daylight saving time.
For reference, on June 21, the longest day of the year, the Sun rises at 5:06 AM and sets 15 hours, 45 minutes later, at 8:51 PM, while on December 21, the shortest day of the year, it rises at 7:36 AM and sets 8 hours, 39 minutes later, at 4:15 PM.
Sunrise & Sunset with Twilight in May
The chance that a given day will be muggy in Umatilla is essentially constant during May, remaining around 0% throughout.
For reference, on July 23, 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 May
The average hourly wind speed in Umatilla is essentially constant during May, remaining within 0.1 miles per hour of 8.7 miles per hour throughout.
For reference, on June 8, the windiest day of the year, the daily average wind speed is 9.0 miles per hour, while on October 6, the calmest day of the year, the daily average wind speed is 7.4 miles per hour.
The lowest daily average wind speed during May is 8.6 miles per hour on May 20.
Average Wind Speed in May
Wind Direction in May
The growing season in Umatilla typically lasts for 5.9 months (179 days), from around April 18 to around October 14, rarely starting before March 29 or after May 9, and rarely ending before September 26 or after November 1.
The month of May in Umatilla is more likely than not fully within the growing season, with the chance that a given day is in the growing season rapidly increasing from 79% to 100% over the course of the month.
Time Spent in Various Temperature Bands and the Growing Season in May
The average accumulated growing degree days in Umatilla are increasing during May, increasing by 353°F, from 279°F to 632°F, over the course of the month.
Growing Degree Days in May
The average daily incident shortwave solar energy in Umatilla is gradually increasing during May, rising by 0.8 kWh, from 6.1 kWh to 6.9 kWh, over the course of the month.
Average Daily Incident Shortwave Solar Energy in May
For the purposes of this report, the geographical coordinates of Umatilla are 45.917 deg latitude, -119.343 deg longitude, and 430 ft elevation.
The topography within 2 miles of Umatilla contains only modest variations in elevation, with a maximum elevation change of 381 feet and an average elevation above sea level of 362 feet. Within 10 miles contains only modest variations in elevation (1,260 feet). Within 50 miles contains very significant variations in elevation (5,659 feet).
The area within 2 miles of Umatilla is covered by shrubs (32%), cropland (24%), water (22%), and artificial surfaces (21%), within 10 miles by cropland (55%) and shrubs (30%), and within 50 miles by shrubs (51%) and cropland (34%).
This report illustrates the typical weather in Umatilla 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 3 weather stations near enough to contribute to our estimation of the temperature and dew point in Umatilla.
For each station, the records are corrected for the elevation difference between that station and Umatilla 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 Umatilla is computed as the weighted average of the individual contributions from each station, with weights proportional to the inverse of the distance between Umatilla and a given station.
The stations contributing to this reconstruction are: Hermiston Municipal Airport (83%, 12 kilometers, southeast); Tri-Cities Airport (15%, 43 kilometers, northeast); and The Dalles Municipal Airport (2.4%, 145 kilometers, west).
Time zones for aiports and weather stations are provided by AskGeo.com .