Average Weather in Riverton Wyoming, United States
In Riverton, the summers are hot and mostly clear; the winters are freezing, windy, and partly cloudy; and it is dry year round. Over the course of the year, the temperature typically varies from 13°F to 89°F and is rarely below -2°F or above 97°F.
The hot season lasts for 3.1 months, from June 8 to September 12, with an average daily high temperature above 78°F. The hottest day of the year is July 19, with an average high of 89°F and low of 61°F.
The cold season lasts for 3.2 months, from November 18 to February 25, with an average daily high temperature below 44°F. The coldest day of the year is January 1, with an average low of 13°F and high of 32°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 Riverton, 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 Riverton begins around June 5 and lasts for 4.3 months, ending around October 14. On August 20, the clearest day of the year, the sky is clear, mostly clear, or partly cloudy 77% of the time, and overcast or mostly cloudy 23% of the time.
The cloudier part of the year begins around October 14 and lasts for 7.7 months, ending around June 5. On March 20, the cloudiest day of the year, the sky is overcast or mostly cloudy 53% of the time, and clear, mostly clear, or partly cloudy 47% 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 Riverton varies throughout the year.
The wetter season lasts 5.8 months, from April 8 to October 2, with a greater than 13% chance of a given day being a wet day. The chance of a wet day peaks at 21% on May 21.
The drier season lasts 6.2 months, from October 2 to April 8. The smallest chance of a wet day is 4% on January 28.
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 in Riverton changes throughout the year.
Rain alone is the most common for 8.8 months, from February 23 to November 19. The highest chance of a day with rain alone is 21% on May 21.
Snow alone is the most common for 3.2 months, from November 19 to February 23. The highest chance of a day with snow alone is 4% on December 11.
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. Riverton experiences some seasonal variation in monthly rainfall.
The rainy period of the year lasts for 6.5 months, from April 3 to October 20, with a sliding 31-day rainfall of at least 0.5 inches. The most rain falls during the 31 days centered around May 19, with an average total accumulation of 1.5 inches.
The rainless period of the year lasts for 5.4 months, from October 20 to April 3. The least rain falls around December 24, with an average total accumulation of 0.1 inches.
Average Monthly Rainfall
The sliding 31-day liquid-equivalent quantity of snowfall in Riverton 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 Riverton varies significantly over the course of the year. In 2017, the shortest day is December 21, with 9 hours, 0 minutes of daylight; the longest day is June 21, with 15 hours, 22 minutes of daylight.
Hours of Daylight and Twilight
The earliest sunrise is at 5:33 AM on June 15, and the latest sunrise is 2 hours, 19 minutes later at 7:52 AM on November 4. The earliest sunset is at 4:38 PM on December 9, and the latest sunset is 4 hours, 18 minutes later at 8:56 PM on June 26.
Daylight saving time (DST) is observed in Riverton 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 Riverton, 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 Riverton experiences mild seasonal variation over the course of the year.
The windier part of the year lasts for 6.4 months, from October 23 to May 4, with average wind speeds of more than 4.6 miles per hour. The windiest day of the year is January 11, with an average hourly wind speed of 5.5 miles per hour.
The calmer time of year lasts for 5.6 months, from May 4 to October 23. The calmest day of the year is August 5, with an average hourly wind speed of 3.7 miles per hour.
Average Wind Speed
The predominant average hourly wind direction in Riverton is from the west throughout the year.
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 3.1 months, from May 14 to August 17, with an average daily incident shortwave energy per square meter above 6.9 kWh. The brightest day of the year is June 29, with an average of 8.2 kWh.
The darker period of the year lasts for 3.5 months, from October 29 to February 13, with an average daily incident shortwave energy per square meter below 3.3 kWh. The darkest day of the year is December 16, with an average of 2.0 kWh.
Average Daily Incident Shortwave Solar Energy
For the purposes of this report, the geographical coordinates of Riverton are 43.025 deg latitude, -108.380 deg longitude, and 4,951 ft elevation.
The topography within 2 miles of Riverton contains only modest variations in elevation, with a maximum elevation change of 197 feet and an average elevation above sea level of 4,946 feet. Within 10 miles contains only modest variations in elevation (853 feet). Within 50 miles contains very significant variations in elevation (8,881 feet).
The area within 2 miles of Riverton is covered by cropland (30%), grassland (30%), shrubs (22%), and artificial surfaces (19%), within 10 miles by shrubs (70%) and cropland (18%), and within 50 miles by shrubs (75%) and grassland (13%).
This report illustrates the typical weather in Riverton, 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 2 weather stations near enough to contribute to our estimation of the temperature and dew point in Riverton.
For each station, the records are corrected for the elevation difference between that station and Riverton 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 Riverton is computed as the weighted average of the individual contributions from each station, with weights proportional to the inverse of the distance between Riverton and a given station.
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.