Vermont Annual Temperatures and Extremes

Vermont's Temperature Records

Hottest temperature ever recorded: 105 F, Vernon, southeastern Vermont, 7/4/1911 Coldest temperature ever recorded: -50 F, Bloomfield, northeastern Vermont, 12/30/1933 Hottest location ranked by highest average annual temperature: Vernon, southeastern Vermont, 46.6 F Coldest location ranked by lowest average annual temperature: Mount Mansfield, north-central Vermont, 34.4 F

The annual mean temperature in Vermont is near 43 degrees Fahrenheit (° F) in the Northeastern Division; 44 in the Southeastern; and 46 in the Western. Averages vary also within the divisions. Elevation, slope, aspect and other local features, including urbanization, all have an effect. As an extreme example of the effect of altitude, a comparison between the station atop Mt. Mansfield’s summit with the Enosburg Falls station is interesting. Though these stations are about the same distance from Lake Champlain, the average temperature is just above freezing at Mt. Mansfield while Enosburg Falls, at 3,500 feet lower elevation, is nearly 10 degrees warmer. The distance between the sites is about 25 miles. The State’s highest temperature recorded is 105° F observed July 4, 1911 at Vernon; the lowest, -50° F, December 30, 1933, at Bloomfield.

Summer temperatures are comfortable as a rule and they are reasonably uniform over Vermont. Thirty-year averages for July remain around 66° F in the northeastern division, 69 in the western division and 67 to 68 in the southeast. Average daily minima reached in July are in the 50s over nearly the entire State. The average daily maxima reach near 80° F. Days with maxima of 90° F or higher average less than 10 per year at most stations. In the coolest summers, days with maximums equal to greater than 90° F range, in frequency of occurrence, from none at many stations to only a few at the warmest stations. In the warmest years many stations still have less than 10, but the frequency ranges up to as high as 30 at the warmer sites. Even after one of these hot days the temperature is likely to fall to 60° F or lower during the night. The average daily range is 20 to 30 degrees in summer, with the variation averaging a little more in the south than in the north. The diurnal range may reach 40° F or more during cool, dry weather in valleys and lowlands. A late spring or early fall freeze is a threat at a few of the more susceptible areas.

Temperatures from place to place vary more in winter than in summer. The Northeastern Division average in January is about 15° F, while for the Southeastern and Western Divisions it is near 19 and 18, respectively. The daily temperature range is less in winter than in summer, averaging near 20 degrees. Days with subzero readings during winter were common at most stations in the early half of the 20th century. They numbered from 10 to 40 per year in the southern portion and from 20 to 50 in the north. The number exceeded 60 at some stations in the coldest winters and could be less than 10 at other stations in the mildest winters. Conversely, winters since 1990 are among the warmest on record. At Burlington in the 1990s, monthly winter temperatures were 3.5 degrees above normal, with 1990 - 1999 containing the 7th-10th warmest winters since the late 1800's.

The growing season for vegetation subject to injury from freezing temperatures averages 130 to 150 days in much of the Western Division and along the Connecticut River in the Southeastern Division. Lake Champlain exerts a moderating influence on the Champlain Valley portion of the western division where the growing season is the longest. Elsewhere the season varies from 100 to 130 days. Local topography causes exceptions and some localities have growing seasons as short as 80 to 90 days. The growing season begins in May and ends in September for most of Vermont.

Vermont precipitation averages and extremes, Top 10 climate extremes, precipitation/temperature data for all U.S. states
Data source: National Climatic Data Center