Sullivan County Climate
Sullivan County, New Hampshire
NOAA NCEI 1991-2020 Climate NormalsAvg Annual Temp
44.3°F
Annual Precip
42.0"
Annual Snowfall
66.1"
Extreme Heat Days
6
days >= 90°F/yr
Monthly Temperature
Precipitation Calendar
Growing Season & Gardening
5b
Minimum winter temperature range for plant survival
2,021
Favors cool-season crops
Seasonal Overview
National Comparison
7-Day Outlook
Forecast
Current Conditions
Air Quality
Safety
Weather Alerts
Climate Advisory: Sullivan County
Climate Verdict
Sullivan County has a cool, averaging 44.3°F annually, moderately wet with 42.0 inches of annual precipitation, rare extreme heat with only 6.3 days above 90°F annually, heavy winter snowfall averaging 66.1 inches per year. This climate profile shapes everything from energy costs to outdoor recreation opportunities.
Seasonal Breakdown
Winters are very cold — January averages 19.2°F. summers are pleasantly cool with July averaging 68.3°F. The 49°F seasonal variation provides noticeable but manageable change.
Outdoor & Gardening Guidance
Winter sports enthusiasts benefit from reliable snow cover for 3-4 months annually.
Regional Context
Sullivan County closely matches the New Hampshire statewide average temperature of 45.4°F, it is somewhat drier than average for New Hampshire.
Climate Profile
About Sullivan County Weather
Sullivan's Cold Northern Reach
Sullivan County maintains a brisk average annual temperature of 44.3°F, placing it nearly 10 degrees below the national median. This region defines the cooler end of the humid continental climate spectrum.
Below the New Hampshire Average
The county sits below the state average annual temperature of 45.4°F and is also slightly drier than most of New Hampshire. It records 42.0 inches of precipitation annually, compared to the 46.4-inch state benchmark.
A More Rugged Interior Climate
Sullivan is much colder and snowier than coastal-adjacent Strafford County, averaging 66.1 inches of snow per year compared to Strafford's 38.9. Its July average of 68.3°F is also two degrees cooler than its eastern neighbors.
Heavy Snow and Brisk Winters
Winter is the dominant season here, with average temperatures of 22.1°F and a January low of 19.2°F. Extreme heat is rare, as the county sees only 6 days a year reaching 90°F or higher.
Gear Up for Serious Snow
With 66.1 inches of annual snowfall, residents require heavy-duty snow removal equipment and dedicated winter tires. Home insulation is a priority given the winter average of 22.1°F, which is lower than many other parts of the state.
Frequently Asked Questions
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Data sources: NOAA National Centers for Environmental Information (NCEI), U.S. Climate Normals 1991-2020. Forecast and alert data from National Weather Service API. Air quality data from Open-Meteo.
Climate normals are 30-year averages of weather variables. Station data is aggregated to county level. Forecasts and alerts are fetched live and may change frequently. Data is informational only — not a substitute for official National Weather Service forecasts or emergency weather warnings.