Average Weather in Fossil Oregon, United States
In Fossil, the summers are short, warm, and mostly clear; the winters are very cold, windy, and partly cloudy; and it is dry year round. Over the course of the year, the temperature typically varies from 24°F to 84°F and is rarely below 12°F or above 93°F.
Based on the tourism score, the best time of year to visit Fossil for warm-weather activities is from mid July to mid August.
The warm season lasts for 2.8 months, from June 19 to September 13, with an average daily high temperature above 75°F. The hottest day of the year is July 30, with an average high of 84°F and low of 53°F.
The cold season lasts for 3.2 months, from November 15 to February 21, with an average daily high temperature below 46°F. The coldest day of the year is December 23, with an average low of 24°F and high of 37°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 Fossil, 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 Fossil begins around June 14 and lasts for 3.7 months, ending around October 4. 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 4 and lasts for 8.3 months, ending around June 14. On January 16, the cloudiest day of the year, the sky is overcast or mostly cloudy 67% of the time, and clear, mostly clear, or partly cloudy 33% 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 Fossil varies throughout the year.
The wetter season lasts 7.9 months, from October 15 to June 11, with a greater than 16% chance of a given day being a wet day. The chance of a wet day peaks at 27% on December 1.
The drier season lasts 4.1 months, from June 11 to October 15. The smallest chance of a wet day is 5% on August 5.
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 22% 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. Fossil experiences some seasonal variation in monthly rainfall.
The rainy period of the year lasts for 9.4 months, from September 22 to July 2, with a sliding 31-day rainfall of at least 0.5 inches. The most rain falls during the 31 days centered around November 18, with an average total accumulation of 1.2 inches.
The rainless period of the year lasts for 2.6 months, from July 2 to September 22. The least rain falls around August 2, with an average total accumulation of 0.3 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. Fossil experiences some seasonal variation in monthly liquid-equivalent snowfall.
The snowy period of the year lasts for 4.0 months, from November 6 to March 6, 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 30, with an average total liquid-equivalent accumulation of 0.4 inches.
The snowless period of the year lasts for 8.0 months, from March 6 to November 6. The least snow falls around August 3, with an average total liquid-equivalent accumulation of 0.0 inches.
Average Liquid-Equivalent Monthly Snowfall
The length of the day in Fossil varies significantly over the course of the year. In 2018, the shortest day is December 21, with 8 hours, 46 minutes of daylight; the longest day is June 21, with 15 hours, 37 minutes of daylight.
Hours of Daylight and Twilight
The earliest sunrise is at 5:13 AM on June 15, and the latest sunrise is 2 hours, 29 minutes later at 7:42 AM on November 3. The earliest sunset is at 4:19 PM on December 9, and the latest sunset is 4 hours, 33 minutes later at 8:51 PM on June 26.
Daylight saving time (DST) is observed in Fossil during 2018, starting in the spring on March 11, lasting 7.8 months, and ending in the fall on November 4.
Sunrise & Sunset with Twilight and Daylight Saving Time
The perceived humidity level in Fossil, 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
The average hourly wind speed in Fossil experiences significant seasonal variation over the course of the year.
The windier part of the year lasts for 5.5 months, from October 29 to April 13, with average wind speeds of more than 8.3 miles per hour. The windiest day of the year is December 1, with an average hourly wind speed of 9.9 miles per hour.
The calmer time of year lasts for 6.5 months, from April 13 to October 29. The calmest day of the year is August 24, with an average hourly wind speed of 6.8 miles per hour.
Average Wind Speed
The predominant average hourly wind direction in Fossil varies throughout the year.
The wind is most often from the west for 7.1 months, from March 14 to October 17, with a peak percentage of 65% on June 21. The wind is most often from the south for 4.9 months, from October 17 to March 14, with a peak percentage of 55% on January 1.
Best Time of Year to Visit
To characterize how pleasant the weather is in Fossil throughout the year, we compute two travel scores.
The tourism score favors clear, rainless days with perceived temperatures between 65°F and 80°F. Based on this score, the best time of year to visit Fossil for general outdoor tourist activities is from mid July to mid August, with a peak score in the last week of July.
The beach/pool score favors clear, rainless days with perceived temperatures between 75°F and 90°F. Based on this score, the best time of year to visit Fossil for hot-weather activities is from mid July to mid August, with a peak score in the last week of July.
For each hour between 8:00 AM and 9:00 PM of each day in the analysis period (1980 to 2016), independent scores are computed for perceived temperature, cloud cover, and total precipitation. Those scores are combined into a single hourly composite score, which is then aggregated into days, averaged over all the years in the analysis period, and smoothed.
Our cloud cover score is 10 for fully clear skies, falling linearly to 9 for mostly clear skies, and to 1 for fully overcast skies.
Our precipitation score, which is based on the three-hour precipitation centered on the hour in question, is 10 for no precipitation, falling linearly to 9 for trace precipitation, and to 0 for 0.04 inches of precipitation or more.
Our tourism temperature score is 0 for perceived temperatures below 50°F, rising linearly to 9 for 65°F, to 10 for 75°F, falling linearly to 9 for 80°F, and to 1 for 90°F or hotter.
Our beach/pool temperature score is 0 for perceived temperatures below 65°F, rising linearly to 9 for 75°F, to 10 for 82°F, falling linearly to 9 for 90°F, and to 1 for 100°F or hotter.
The growing season in Fossil typically lasts for 4.6 months (141 days), from around May 12 to around September 30, rarely starting before April 22 or after May 29, and rarely ending before September 12 or after October 18.
Time Spent in Various Temperature Bands and the Growing Season
Based on growing degree days alone, the first spring blooms in Fossil should appear around April 26, only rarely appearing before April 12 or after May 12.
Growing Degree Days
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 3.0 months, from May 24 to August 23, with an average daily incident shortwave energy per square meter above 6.5 kWh. The brightest day of the year is July 14, with an average of 7.8 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 2.6 kWh. The darkest day of the year is December 26, with an average of 1.3 kWh.
Average Daily Incident Shortwave Solar Energy
For the purposes of this report, the geographical coordinates of Fossil are 44.998 deg latitude, -120.216 deg longitude, and 3,196 ft elevation.
The topography within 2 miles of Fossil contains very significant variations in elevation, with a maximum elevation change of 1,135 feet and an average elevation above sea level of 2,962 feet. Within 10 miles contains very significant variations in elevation (3,212 feet). Within 50 miles contains large variations in elevation (6,647 feet).
The area within 2 miles of Fossil is covered by shrubs (95%), within 10 miles by shrubs (95%), and within 50 miles by shrubs (81%).
This report illustrates the typical weather in Fossil, 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 Fossil.
For each station, the records are corrected for the elevation difference between that station and Fossil 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 Fossil is computed as the weighted average of the individual contributions from each station, with weights proportional to the inverse of the distance between Fossil and a given station.
The stations contributing to this reconstruction are: The Dalles Municipal Airport (22%, 102 kilometers, northwest); Roberts Field-Redmond Municipal Airport (30%, 110 kilometers, southwest); Hermiston Municipal Airport (21%, 119 kilometers, northeast); and John Day State Airport (27%, 119 kilometers, southeast).
Time zones for aiports and weather stations are provided by AskGeo.com .