Average Weather in Jamestown New York, United States
In Jamestown, the temperature typically varies from 17°F to 78°F over the course of the year, and is rarely below 1°F or above 86°F.
The warm season lasts for 119 days, from May 23 to September 19, with an average daily high temperature above 68°F. The hottest day of the year is July 20, with an average high of 78°F and low of 61°F.
The cold season lasts for 99 days, from December 2 to March 11, with an average daily high temperature below 40°F. The coldest day of the year is January 29, with an average low of 17°F and high of 30°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 9 hours, 6 minutes of daylight; the longest day is June 21, with 15 hours, 15 minutes of daylight.
Hours of Daylight and Twilight
The earliest sunrise is at 5:40 AM on June 14, and the latest sunrise is 2 hours, 13 minutes later at 7:53 AM on November 4. The earliest sunset is at 4:45 PM on December 8, and the latest sunset is 4 hours, 12 minutes later at 8:56 PM on June 26.
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 April 18 and lasts for 206 days, ending around November 10. On August 9, the clearest day of the year, the sky is clear, mostly clear, or partly cloudy 65% of the time, and overcast or mostly cloudy 35% of the time.
The cloudier part of the year begins around November 10 and lasts for 159 days, ending around April 18. On January 11, the cloudiest day of the year, the sky is overcast or mostly cloudy 77% of the time, and clear, mostly clear, or partly cloudy 23% 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 throughout the year.
The wetter season lasts 273 days, from March 19 to December 17, with a greater than 28% chance of a given day being a wet day. The chance of a wet day peaks at 39% on June 15.
The drier season lasts 92 days, from December 17 to March 19. The smallest chance of a wet day is 17% on January 30.
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 39% on June 15.
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.
Rain falls throughout the year in Jamestown. The most rain falls during the 31 days centered around July 27, with an average total accumulation of 3.3 inches.
The least rain falls around February 7, with and average total accumulation of 0.9 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 163 days, from November 2 to April 14, 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 23, with an average total liquid-equivalent accumulation of 0.6 inches.
The snowless period of the year lasts for 202 days, from April 14 to November 2. The least snow falls around July 28, 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 106 days, from June 3 to September 17, during which time the comfort level is muggy, oppressive, or miserable at least 5% of the time. The muggiest day of the year is August 1, with muggy conditions 19% of the time.
The least muggy day of the year is November 29, 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 151 days, from November 11 to April 11, with average wind speeds of more than 3.6 miles per hour. The windiest day of the year is January 17, with an average hourly wind speed of 5.1 miles per hour.
The calmer time of year lasts for 214 days, from April 11 to November 11. The calmest day of the year is August 4, with an average hourly wind speed of 2.3 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 south for 46 days, from September 10 to October 26, with a peak percentage of 38% on November 14. The wind is most often from the west for 319 days, from October 26 to September 10, with a peak percentage of 50% on January 29.
Jamestown 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 experiences significant seasonal variation over the course of the year.
The time of year with warmer water lasts for 94 days, from June 26 to September 28, with an average temperature above 65°F. The day of the year with the warmest water is August 7, with an average temperature of 73°F.
The time of year with cooler water lasts for 131 days, from December 22 to May 2, with an average temperature below 42°F. The day of the year with the coolest water is February 27, with an average temperature of 34°F.
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 112 days, from May 4 to August 24, with an average daily incident shortwave energy per square meter above 5.7 kWh. The brightest day of the year is June 30, with an average of 6.9 kWh.
The darker period of the year lasts for 107 days, from November 1 to February 16, 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 1.3 kWh.
Average Daily Incident Shortwave Solar Energy
For the purposes of this report, the geographical coordinates of Jamestown are 42.097 deg latitude, -79.235 deg longitude, and 1,411 ft elevation (map ).
The topography within 2 miles of Jamestown contains only modest variations in elevation, with a maximum elevation change of 371 feet, and an average elevation above sea level of 1,422 feet. Within 10 miles contains very significant variations in elevation (965 feet). Within 50 miles also contains very significant variations in elevation (1,877 feet).
The area within 2 miles of Jamestown is covered by artificial surfaces (64%), trees (22%), and cropland (10%), within 10 miles by trees (64%) and cropland (25%), and within 50 miles by trees (64%) and water (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 3 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: Chautauqua County-Jamestown Airport (90%, 6 kilometers, north), Bradford Regional Airport (7%, 60 kilometers, southeast), and Venango Regional Airport (3.6%, 95 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 .