This report describes the typical weather at the Chautauqua County-Jamestown Airport (Jamestown, New York, United States) weather station over the course of an average year. It is based on the historical records from 1984 to 2012. Earlier records are either unavailable or unreliable.
Jamestown, New York has a humid continental climate with warm summers and no dry season. The area within 25 mi of this station is covered by forests (91%) and oceans and seas (4%).
Over the course of a year, the temperature typically varies from 17Â°F to 77Â°F and is rarely below 2Â°F or above 85Â°F.
The warm season lasts from May 27 to September 18 with an average daily high temperature above 67Â°F. The hottest day of the year is July 25, with an average high of 77Â°F and low of 61Â°F.
The cold season lasts from December 1 to March 10 with an average daily high temperature below 38Â°F. The coldest day of the year is January 23, with an average low of 17Â°F and high of 29Â°F.
The length of the day varies significantly over the course of the year. The shortest day is December 21 with 9:06 hours of daylight; the longest day is June 20 with 15:16 hours of daylight.
The earliest sunrise is at 5:40am on June 12 and the latest sunset is at 8:58pm on June 29. The latest sunrise is at 7:53am on November 3 and the earliest sunset is at 4:45pm on December 7.
Daylight savings time (DST) is observed in this location during 2012, starting in the spring on March 11 and ending in the fall on November 4.
The median cloud cover ranges from 58% (partly cloudy) to 100% (overcast). The sky is cloudiest on January 1 and clearest on July 19. The clearer part of the year begins around April 21. The cloudier part of the year begins around October 4.
On July 19, the clearest day of the year, the sky is clear, mostly clear, or partly cloudy 42% of the time, and overcast or mostly cloudy 40% of the time.
On January 1, the cloudiest day of the year, the sky is overcast, mostly cloudy, or partly cloudy 74% of the time, and clear or mostly clear 11% of the time.
The probability that precipitation will be observed at this location varies throughout the year. Precipitation is most likely around January 18, occurring in 60% of days. Precipitation is least likely around September 11, occurring in 35% of days.
Over the entire year, the most common forms of precipitation are light rain, light snow, and thunderstorms.
Light rain is the most severe precipitation observed during 37% of those days with precipitation. It is most likely around October 12, when it is observed during 26% of all days.
Light snow is the most severe precipitation observed during 36% of those days with precipitation. It is most likely around January 16, when it is observed during 43% of all days.
Thunderstorms are the most severe precipitation observed during 16% of those days with precipitation. They are most likely around July 12, when it is observed during 20% of all days.
During the warm season, which lasts from May 27 to September 18, there is a 37% average chance that precipitation will be observed at some point during a given day. When precipitation does occur it is most often in the form of light rain (49% of days with precipitation have at worst light rain) and thunderstorms (43%).
During the cold season, which lasts from December 1 to March 10, there is a 57% average chance that precipitation will be observed at some point during a given day. When precipitation does occur it is most often in the form of light snow (68% of days with precipitation have at worst light snow), light rain (16%), and moderate snow (7%).
The likelihood of snow falling is highest around January 17, occurring in 50% of days. The season in which it is relatively likely for snow to fall spans from November 3 to April 15.
Either snow rarely accumulates at this location or snow depth measurements are unavailable or unreliable.
The relative humidity typically ranges from 43% (comfortable) to 92% (very humid) over the course of the year, rarely dropping below 24% (dry) and reaching as high as 100% (very humid).
The air is driest around May 4, at which time the relative humidity drops below 52% (mildly humid) three days out of four; it is most humid around September 18, exceeding 88% (very humid) three days out of four.
Dew point is often a better measure of how comfortable a person will find the weather than relative humidity because it more directly relates to whether perspiration will evaporate from the skin, thereby cooling the body. Lower dew points feel drier and higher dew points feel more humid.
Over the course of a year, the dew point typically varies from 10Â°F (dry) to 64Â°F (mildy humid) and is rarely below -5Â°F (dry) or above 71Â°F (muggy).
The time of the year between May 20 and October 3 is the most comfortable, with dew points that are neither too dry nor too muggy.
Over the course of the year typical wind speeds vary from 0 mph to 16 mph (calm to moderate breeze), rarely exceeding 22 mph (fresh breeze).
The highest average wind speed of 10 mph (gentle breeze) occurs around December 25, at which time the average daily maximum wind speed is 16 mph (moderate breeze).
The lowest average wind speed of 6 mph (light breeze) occurs around August 4, at which time the average daily maximum wind speed is 12 mph (gentle breeze).