Average Weather in Jamestown North Dakota, United States
In Jamestown, the temperature typically varies from 3°F to 83°F over the course of the year, and is rarely below -17°F or above 92°F.
The warm season lasts for 119 days, from May 22 to September 18, with an average daily high temperature above 70°F. The hottest day of the year is July 24, with an average high of 83°F and low of 60°F.
The cold season lasts for 102 days, from November 25 to March 7, with an average daily high temperature below 33°F. The coldest day of the year is January 15, with an average low of 3°F and high of 20°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 Jamestown varies significantly over the course of the year. In 2017, the shortest day is December 21, with 8 hours, 31 minutes of daylight; the longest day is June 21, with 15 hours, 53 minutes of daylight.
Hours of Daylight and Twilight
The earliest sunrise is at 5:39 AM on June 15, and the latest sunrise is 2 hours, 43 minutes later at 8:22 AM on November 4. The earliest sunset is at 4:45 PM on December 10, and the latest sunset is 4 hours, 48 minutes later at 9:33 PM on June 25.
Daylight saving time (DST) is observed in Jamestown during 2017, starting in the spring on March 12, lasting 237 days, and ending in the fall on November 5.
Sunrise & Sunset with Twilight and Daylight Saving Time
In Jamestown, 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 Jamestown begins around June 7 and lasts for 127 days, ending around October 12. On July 27, the clearest day of the year, the sky is clear, mostly clear, or partly cloudy 74% of the time, and overcast or mostly cloudy 26% of the time.
The cloudier part of the year begins around October 12 and lasts for 238 days, ending around June 7. On February 4, the cloudiest day of the year, the sky is overcast or mostly cloudy 62% of the time, and clear, mostly clear, or partly cloudy 38% 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 Jamestown varies significantly throughout the year.
The wetter season lasts 140 days, from April 28 to September 15, with a greater than 20% chance of a given day being a wet day. The chance of a wet day peaks at 36% on June 12.
The drier season lasts 225 days, from September 15 to April 28. 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 Jamestown changes throughout the year.
Rain alone is the most common for 241 days, from March 18 to November 14. The highest chance of a day with rain alone is 36% on June 12.
Snow alone is the most common for 124 days, from November 14 to March 18. The highest chance of a day with snow alone is 6% on January 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 in the year. Jamestown experiences significant seasonal variation in monthly rainfall.
The rainy period of the year lasts for 226 days, from March 26 to November 7, with a sliding 31-day rainfall of at least 0.5 inches. The most rain falls during the 31 days centered around June 19, with an average total accumulation of 3.1 inches.
The rainless period of the year lasts for 139 days, from November 7 to March 26. The least rain falls around January 1, with and average total accumulation of 0.0 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 in the year. Jamestown experiences some seasonal variation in monthly liquid-equivalent snowfall.
The snowy period of the year lasts for 185 days, from October 26 to April 29, 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 4, with an average total liquid-equivalent accumulation of 0.3 inches.
The snowless period of the year lasts for 180 days, from April 29 to October 26. The least snow falls around July 26, with an average total liquid-equivalent accumulation of 0.0 inches.
Average Liquid-Equivalent Monthly Snowfall
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.
Jamestown experiences some seasonal variation in the perceived humidity.
The muggier period of the year lasts for 87 days, from June 13 to September 8, during which time the comfort level is muggy, oppressive, or miserable at least 5% of the time. The muggiest day of the year is July 24, with muggy conditions 18% of the time.
The least muggy day of the year is March 1, when muggy conditions are essentially unheard of.
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 Jamestown experiences mildly seasonal variation over the course of the year.
The windier part of the year lasts for 265 days, from September 13 to June 5, with average wind speeds of more than 5.9 miles per hour. The windiest day of the year is March 21, with an average hourly wind speed of 6.9 miles per hour.
The calmer time of year lasts for 100 days, from June 5 to September 13. The calmest day of the year is July 27, with an average hourly wind speed of 5.1 miles per hour.
Average Wind Speed
The predominant average hourly wind direction in Jamestown varies throughout the year.
The wind is most often from the north for 88 days, from February 16 to May 15, with a peak percentage of 35% on April 11. The wind is most often from the south for 125 days, from May 15 to September 17, with a peak percentage of 35% on August 20. The wind is most often from the west for 152 days, from September 17 to February 16, with a peak percentage of 42% on January 4.
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 108 days, from May 3 to August 19, with an average daily incident shortwave energy per square meter above 6.0 kWh. The brightest day of the year is July 8, with an average of 7.2 kWh.
The darker period of the year lasts for 109 days, from October 27 to February 13, with an average daily incident shortwave energy per square meter below 2.5 kWh. The darkest day of the year is December 25, with an average of 1.3 kWh.
Average Daily Incident Shortwave Solar Energy
For the purposes of this report, the geographical coordinates of Jamestown are 46.911 deg latitude, -98.708 deg longitude, and 1,486 ft elevation (map ).
The topography within 2 miles of Jamestown contains only modest variations in elevation, with a maximum elevation change of 131 feet, and an average elevation above sea level of 1,452 feet. Within 10 miles also contains only modest variations in elevation (262 feet). Within 50 miles contains very significant variations in elevation (1,152 feet).
The area within 2 miles of Jamestown is covered by cropland (60%) and artificial surfaces (37%), within 10 miles by cropland (91%), and within 50 miles by cropland (77%) and grassland (19%).
This report illustrates the typical weather in Jamestown, 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 5 weather stations near enough to contribute to our estimation of the temperature and dew point in Jamestown.
For each station, the records are corrected for the elevation difference between that station and Jamestown 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 Jamestown is computed as the weighted average of the individual contributions from each station, with weights proportional to the inverse of the distance between Jamestown and a given station.
The stations contributing to this reconstruction are: Jamestown Municipal Airport (98%, 3.5 kilometers, northeast), Carrington Municipal Airport (1.1%, 69 kilometers, northwest), Ashley Municipal Airport (0.4%, 141 kilometers, southwest), Bismarck Municipal Airport (0.3%, 157 kilometers, west), and Aberdeen Regional Airport (0.3%, 165 kilometers, south).
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 .