30-year climate normals

Jefferson County Climate and Weather Averages

Hottest month — July

79.2°

average daily high. The coldest month is January, averaging a low of 10.0°F.

Jefferson County gets 37.07" of precipitation a year, and 30% of it falls in Sep, Oct, Nov.

Temperature through the year

Each bar spans the average daily low to the average daily high for that month.

Month	Avg high	Avg low	Precip
January	29.8°	10.0°	2.86"
February	31.4°	10.7°	2.18"
March	40.0°	20.7°	2.37"
April	53.7°	32.5°	3.07"
May	66.2°	43.7°	2.97"
June	74.5°	53.1°	3.09"
July	79.2°	58.8°	3.01"
August	78.2°	56.7°	3.20"
September	71.2°	48.8°	3.56"
October	58.4°	39.2°	4.22"
November	46.6°	29.5°	3.40"
December	35.5°	19.0°	3.14"

Rainfall by month

Precipitation is spread fairly evenly through the year here, with 30% falling in the wettest three months (Sep, Oct, Nov).

January 2.86"

February 2.18"

March 2.37"

April 3.07"

May 2.97"

June 3.09"

July 3.01"

August 3.20"

September 3.56"

October 4.22"

November 3.40"

December 3.14"

Annual total 37.07"

What this climate costs you

Degree days measure how hard a building has to work to stay comfortable. They are the reason two identical houses have very different power bills, and they are the link between the weather here and what you pay every month.

Cooling degree days How much air conditioning the climate demands 386

Heating degree days How much heating the climate demands 7,524

Approximate annual cooling cost At 29.93¢/kWh, New York average $116

Approximate annual electric heating cost Lower where heating is gas rather than electric $788

These are rough planning figures from degree days and the state electricity price, not a bill estimate. House size, insulation and fuel type move them a lot. See the full cost of owning a home in Jefferson County, where electricity is one line of eight.

Common questions

What is the weather like in Jefferson County?

Jefferson County averages a high of 79.2°F in July and a low of 10.0°F in January. Annual precipitation is 37.07 inches, with essentially no snow.

When is the rainy season in Jefferson County?

The wettest stretch is Sep, Oct, Nov, which accounts for 30% of the year's precipitation. Precipitation is relatively evenly distributed across the year.

How hot does it get in Jefferson County?

The average daily high in July, the hottest month, is 79.2°F. That drives 386 cooling degree days a year, which is what your air conditioning has to work against.

Does it snow in Jefferson County?

Effectively no. Measurable snowfall is rare in Jefferson County.

Sources

Temperature, precipitation and snowfall normals — NOAA National Centers for Environmental Information, 1991–2020 Monthly Climate Normals, station WATERTOWN INTL AP, NY US (USW00094790), 1.6 miles from the county centroid.
Heating and cooling degree days — NOAA, same station and period.
Electricity price — US Energy Information Administration, Electric Power Monthly Table 5.6.A, New York residential average.
Wet-season share is the wettest three consecutive months as a percentage of annual precipitation, calculated from the monthly normals.