Average Weather in Pomeroy Washington, United States
In Pomeroy, the summers are short, warm, dry, and mostly clear and the winters are very cold and partly cloudy. Over the course of the year, the temperature typically varies from 27°F to 88°F and is rarely below 14°F or above 97°F.
Based on the tourism score, the best time of year to visit Pomeroy for warm-weather activities is from early July to late August.
The hot season lasts for 2.6 months, from June 23 to September 11, with an average daily high temperature above 78°F. The hottest day of the year is August 3, with an average high of 88°F and low of 58°F.
The cold season lasts for 3.4 months, from November 13 to February 23, with an average daily high temperature below 46°F. The coldest day of the year is December 23, with an average low of 27°F and high of 36°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 Pomeroy, 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 Pomeroy begins around June 13 and lasts for 3.9 months, ending around October 8. On July 29, the clearest day of the year, the sky is clear, mostly clear, or partly cloudy 81% of the time, and overcast or mostly cloudy 19% of the time.
The cloudier part of the year begins around October 8 and lasts for 8.1 months, ending around June 13. On January 15, 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 Pomeroy varies throughout the year.
The wetter season lasts 7.5 months, from October 21 to June 6, with a greater than 22% chance of a given day being a wet day. The chance of a wet day peaks at 37% on November 28.
The drier season lasts 4.5 months, from June 6 to October 21. The smallest chance of a wet day is 7% 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 32% 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. Pomeroy experiences some seasonal variation in monthly rainfall.
The rainy period of the year lasts for 11 months, from August 27 to July 17, with a sliding 31-day rainfall of at least 0.5 inches. The most rain falls during the 31 days centered around November 20, with an average total accumulation of 2.0 inches.
The rainless period of the year lasts for 1.3 months, from July 17 to August 27. The least rain falls around August 5, with an average total accumulation of 0.4 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. Pomeroy experiences some seasonal variation in monthly liquid-equivalent snowfall.
The snowy period of the year lasts for 3.6 months, from November 15 to March 2, with a sliding 31-day liquid-equivalent snowfall of at least 0.1 inches. The most snow falls during the 31 days centered around January 1, with an average total liquid-equivalent accumulation of 0.5 inches.
The snowless period of the year lasts for 8.4 months, from March 2 to November 15. The least snow falls around July 19, with an average total liquid-equivalent accumulation of 0.0 inches.
Average Liquid-Equivalent Monthly Snowfall
The length of the day in Pomeroy varies significantly over the course of the year. In 2017, the shortest day is December 21, with 8 hours, 35 minutes of daylight; the longest day is June 20, with 15 hours, 49 minutes of daylight.
Hours of Daylight and Twilight
The earliest sunrise is at 4:56 AM on June 15, and the latest sunrise is 2 hours, 40 minutes later at 7:36 AM on November 4. The earliest sunset is at 4:03 PM on December 10, and the latest sunset is 4 hours, 44 minutes later at 8:47 PM on June 25.
Daylight saving time (DST) is observed in Pomeroy 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
The perceived humidity level in Pomeroy, 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 Pomeroy experiences mild seasonal variation over the course of the year.
The windier part of the year lasts for 6.0 months, from October 25 to April 26, with average wind speeds of more than 8.3 miles per hour. The windiest day of the year is November 19, with an average hourly wind speed of 9.2 miles per hour.
The calmer time of year lasts for 6.0 months, from April 26 to October 25. The calmest day of the year is August 12, with an average hourly wind speed of 7.5 miles per hour.
Average Wind Speed
The predominant average hourly wind direction in Pomeroy varies throughout the year.
The wind is most often from the west for 7.2 months, from March 12 to October 19, with a peak percentage of 57% on June 20. The wind is most often from the south for 4.8 months, from October 19 to March 12, with a peak percentage of 55% on January 1.
Best Time of Year to Visit
To characterize how pleasant the weather is in Pomeroy 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 Pomeroy for general outdoor tourist activities is from early July to late August, with a peak score in the first week of August.
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 Pomeroy 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 Pomeroy typically lasts for 6.0 months (182 days), from around April 21 to around October 19, rarely starting before March 29 or after May 12, and rarely ending before September 30 or after November 7.
Time Spent in Various Temperature Bands and the Growing Season
Based on growing degree days alone, the first spring blooms in Pomeroy should appear around April 24, only rarely appearing before April 11 or after May 9.
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 3.1 months, from May 19 to August 22, with an average daily incident shortwave energy per square meter above 6.4 kWh. The brightest day of the year is July 13, with an average of 7.7 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 2.5 kWh. The darkest day of the year is December 23, with an average of 1.2 kWh.
Average Daily Incident Shortwave Solar Energy
For the purposes of this report, the geographical coordinates of Pomeroy are 46.475 deg latitude, -117.603 deg longitude, and 2,274 ft elevation.
The topography within 2 miles of Pomeroy contains significant variations in elevation, with a maximum elevation change of 791 feet and an average elevation above sea level of 2,184 feet. Within 10 miles contains significant variations in elevation (3,225 feet). Within 50 miles contains large variations in elevation (5,938 feet).
The area within 2 miles of Pomeroy is covered by grassland (39%), cropland (31%), and shrubs (30%), within 10 miles by grassland (37%) and cropland (32%), and within 50 miles by cropland (38%) and shrubs (31%).
This report illustrates the typical weather in Pomeroy, 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 Pomeroy.
For each station, the records are corrected for the elevation difference between that station and Pomeroy 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 Pomeroy is computed as the weighted average of the individual contributions from each station, with weights proportional to the inverse of the distance between Pomeroy and a given station.
The stations contributing to this reconstruction are: Lewiston–Nez Perce County Airport (34%, 46 kilometers, east); Pullman–Moscow Regional Airport (39%, 48 kilometers, northeast); Walla Walla Regional Airport (20%, 68 kilometers, southwest); and Grant County International Airport (7%, 154 kilometers, northwest).
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.
Time zones for aiports and weather stations are provided by AskGeo.com .