Average Weather in Eugene Oregon, United States
In Eugene, the summers are short, warm, dry, and mostly clear and the winters are chilly, wet, and overcast. Over the course of the year, the temperature typically varies from 35°F to 86°F and is rarely below 25°F or above 97°F.
The hot season lasts for 2.8 months, from June 26 to September 19, with an average daily high temperature above 78°F. The hottest day of the year is August 3, with an average high of 86°F and low of 55°F.
The cool season lasts for 3.5 months, from November 12 to February 25, with an average daily high temperature below 54°F. The coldest day of the year is December 23, with an average low of 35°F and high of 46°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 Eugene, 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 Eugene begins around June 12 and lasts for 3.9 months, ending around October 10. On July 27, the clearest day of the year, the sky is clear, mostly clear, or partly cloudy 83% of the time, and overcast or mostly cloudy 17% of the time.
The cloudier part of the year begins around October 10 and lasts for 8.1 months, ending around June 12. On December 26, the cloudiest day of the year, the sky is overcast or mostly cloudy 76% of the time, and clear, mostly clear, or partly cloudy 24% 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 Eugene varies very significantly throughout the year.
The wetter season lasts 6.8 months, from October 15 to May 9, with a greater than 31% chance of a given day being a wet day. The chance of a wet day peaks at 58% on November 28.
The drier season lasts 5.2 months, from May 9 to October 15. The smallest chance of a wet day is 3% 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 56% on November 28.
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. Eugene experiences extreme seasonal variation in monthly rainfall.
The rainy period of the year lasts for 11 months, from August 19 to July 14, with a sliding 31-day rainfall of at least 0.5 inches. The most rain falls during the 31 days centered around December 2, with an average total accumulation of 9.4 inches.
The rainless period of the year lasts for 1.2 months, from July 14 to August 19. The least rain falls around July 31, with an average total accumulation of 0.3 inches.
Average Monthly Rainfall
The sliding 31-day liquid-equivalent quantity of snowfall in Eugene does not vary significantly over the course of the year, staying within 0.1 inches of 0.1 inches throughout.
Average Liquid-Equivalent Monthly Snowfall
The length of the day in Eugene varies significantly over the course of the year. In 2017, the shortest day is December 21, with 8 hours, 53 minutes of daylight; the longest day is June 20, with 15 hours, 30 minutes of daylight.
Hours of Daylight and Twilight
The earliest sunrise is at 5:28 AM on June 15, and the latest sunrise is 2 hours, 25 minutes later at 7:53 AM on November 4. The earliest sunset is at 4:34 PM on December 9, and the latest sunset is 4 hours, 26 minutes later at 8:59 PM on June 26.
Daylight saving time (DST) is observed in Eugene 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 Eugene, 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 Eugene does not vary significantly over the course of the year, remaining within 0.4 miles per hour of 2.2 miles per hour throughout.
Average Wind Speed
The predominant average hourly wind direction in Eugene varies throughout the year.
The wind is most often from the west for 1.8 months, from April 13 to June 7, with a peak percentage of 42% on May 28. The wind is most often from the north for 4.1 months, from June 7 to October 10, with a peak percentage of 61% on July 22. The wind is most often from the south for 6.1 months, from October 10 to April 13, with a peak percentage of 54% 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 2.9 months, from May 30 to August 26, with an average daily incident shortwave energy per square meter above 6.1 kWh. The brightest day of the year is July 16, with an average of 7.5 kWh.
The darker period of the year lasts for 3.9 months, from October 27 to February 23, 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 1.1 kWh.
Average Daily Incident Shortwave Solar Energy
For the purposes of this report, the geographical coordinates of Eugene are 44.052 deg latitude, -123.087 deg longitude, and 427 ft elevation.
The topography within 2 miles of Eugene contains only modest variations in elevation, with a maximum elevation change of 463 feet and an average elevation above sea level of 438 feet. Within 10 miles contains only modest variations in elevation (2,142 feet). Within 50 miles contains large variations in elevation (6,096 feet).
The area within 2 miles of Eugene is covered by artificial surfaces (94%), within 10 miles by cropland (46%) and artificial surfaces (23%), and within 50 miles by trees (61%) and shrubs (20%).
This report illustrates the typical weather in Eugene, 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 Eugene.
For each station, the records are corrected for the elevation difference between that station and Eugene 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 Eugene is computed as the weighted average of the individual contributions from each station, with weights proportional to the inverse of the distance between Eugene and a given station.
The stations contributing to this reconstruction are: Mahlon Sweet Field Airport (93%, 14 kilometers, northwest); Roseburg Municipal Airport (5%, 93 kilometers, south); and Bend Municipal Airport (2.0%, 151 kilometers, east).
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.