Coos County Climate
Coos County, New Hampshire
Avg Annual Temp
40.0°F
Annual Precip
47.9"
Annual Snowfall
118.8"
Extreme Heat Days
1.7363636363636366
days >= 90°F/yr
Monthly Temperature
Precipitation Calendar
Seasonal Overview
National Comparison
Climate Profile
About Coos County Weather
The Coldest Reach of the State
Coos County is one of the coldest spots in the country with an annual average of only 40.0°F. This is more than 13 degrees below the national median, marking a truly boreal climate.
New Hampshire's Ice Box
Coos is the coldest county in the state, trailing the New Hampshire average by a wide 5.4-degree margin. Its extreme northern location creates a climate distinct from the rest of the region.
Leading the Region in Snowfall
With 118.8 inches of annual snow, Coos far exceeds the 83.5 inches seen in neighboring Carroll County. It is the snowiest and coldest part of the entire state.
Severe Winters and Rare Heat
Winter is the dominant season here, with average temperatures dipping to 16.7°F. Extreme heat is nearly non-existent, as the county averages only 2 days per year over 90°F.
Maximum Winter Readiness Required
Residents must prioritize heavy-duty heating and professional-grade snow equipment for the 118.8-inch annual snowfall. Summer gear is rarely stressed, as July averages stay cool at 64.3°F.
Frequently Asked Questions
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Data source: NOAA National Centers for Environmental Information (NCEI), U.S. Climate Normals 1991-2020.
Climate normals are 30-year averages of weather variables computed from 1991 to 2020. Station data is aggregated to county level using spatial averaging. Data is informational only — not a substitute for official National Weather Service forecasts or emergency weather warnings.