Average Weather in Grants Pass Oregon, United States
In Grants Pass, the temperature typically varies from 36°F to 90°F over the course of the year, and is rarely below 27°F or above 98°F.
The hot season lasts for 2.9 months, from June 22 to September 20, with an average daily high temperature above 81°F. The hottest day of the year is August 3, with an average high of 90°F and low of 60°F.
The cool season lasts for 3.5 months, from November 11 to February 26, with an average daily high temperature below 56°F. The coldest day of the year is December 23, with an average low of 36°F and high of 48°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 Grants Pass varies significantly over the course of the year. In 2017, the shortest day is December 21, with 9 hours, 4 minutes of daylight; the longest day is June 21, with 15 hours, 18 minutes of daylight.
Hours of Daylight and Twilight
The earliest sunrise is at 5:35 AM on June 14, and the latest sunrise is 2 hours, 15 minutes later at 7:51 AM on November 4. The earliest sunset is at 4:40 PM on December 7, and the latest sunset is 4 hours, 14 minutes later at 8:54 PM on June 26.
Daylight saving time (DST) is observed in Grants Pass 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
In Grants Pass, 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 Grants Pass begins around June 12 and lasts for 4.0 months, ending around October 13. On August 3, the clearest day of the year, the sky is clear, mostly clear, or partly cloudy 87% of the time, and overcast or mostly cloudy 13% of the time.
The cloudier part of the year begins around October 13 and lasts for 8.0 months, ending around June 12. On November 30, the cloudiest day of the year, the sky is overcast or mostly cloudy 72% of the time, and clear, mostly clear, or partly cloudy 28% 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 Grants Pass varies significantly throughout the year.
The wetter season lasts 6.2 months, from October 23 to April 28, with a greater than 28% chance of a given day being a wet day. The chance of a wet day peaks at 52% on November 30.
The drier season lasts 5.8 months, from April 28 to October 23. The smallest chance of a wet day is 2% on August 3.
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 51% on November 30.
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. Grants Pass experiences very significant seasonal variation in monthly rainfall.
The rainy period of the year lasts for 9.8 months, from September 2 to June 27, with a sliding 31-day rainfall of at least 0.5 inches. The most rain falls during the 31 days centered around December 7, with an average total accumulation of 8.3 inches.
The rainless period of the year lasts for 2.2 months, from June 27 to September 2. The least rain falls around July 30, with and average total accumulation of 0.2 inches.
Average Monthly Rainfall
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 Grants Pass, 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 Grants Pass does not vary significantly over the course of the year, remaining within 0.2 miles per hour of 2.2 miles per hour throughout.
Average Wind Speed
The predominant average hourly wind direction in Grants Pass varies throughout the year.
The wind is most often from the west for 1.3 weeks, from April 11 to April 20, with a peak percentage of 31% on May 29. The wind is most often from the north for 5.8 months, from April 20 to October 14, with a peak percentage of 68% on July 18. The wind is most often from the south for 5.9 months, from October 14 to April 11, with a peak percentage of 49% on November 27.
Grants Pass is located near a large body of water (e.g., ocean, sea, or large lake). This section reports on the wide-area average surface temperature of that water.The average water temperature does not vary significantly over the course of the year, remaining within 2°F of 52°F throughout.
Average Water Temperature
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 3.1 months, from May 24 to August 26, with an average daily incident shortwave energy per square meter above 6.6 kWh. The brightest day of the year is July 14, with an average of 8.0 kWh.
The darker period of the year lasts for 3.8 months, from October 29 to February 21, with an average daily incident shortwave energy per square meter below 2.8 kWh. The darkest day of the year is December 26, with an average of 1.4 kWh.
Average Daily Incident Shortwave Solar Energy
For the purposes of this report, the geographical coordinates of Grants Pass are 42.439 deg latitude, -123.331 deg longitude, and 1,083 ft elevation.
The topography within 2 miles of Grants Pass contains very significant variations in elevation, with a maximum elevation change of 1,207 feet, and an average elevation above sea level of 1,043 feet. Within 10 miles contains extreme variations in elevation (3,632 feet). Within 50 miles also contains extreme variations in elevation (7,428 feet).
The area within 2 miles of Grants Pass is covered by artificial surfaces (58%) and shrubs (31%), within 10 miles by shrubs (61%) and trees (26%), and within 50 miles by trees (56%) and shrubs (39%).
This report illustrates the typical weather in Grants Pass, 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 Grants Pass.
For each station, the records are corrected for the elevation difference between that station and Grants Pass 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 Grants Pass is computed as the weighted average of the individual contributions from each station, with weights proportional to the inverse of the distance between Grants Pass and a given station.
The stations contributing to this reconstruction are: Sexton Summit, (19%, 18 kilometers, north), Rogue Valley International - Medford Airport (63%, 38 kilometers, east), and Brookings Airport (18%, 89 kilometers, southwest).
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 .