Coos County Climate
Coos County, New Hampshire
NOAA NCEI 1991-2020 Climate NormalsAvg Annual Temp
40.0°F
Annual Precip
47.9"
Annual Snowfall
118.8"
Extreme Heat Days
2
days >= 90°F/yr
Monthly Temperature
Precipitation Calendar
Growing Season & Gardening
4b
Minimum winter temperature range for plant survival
1,542
Favors cool-season crops
Seasonal Overview
National Comparison
7-Day Outlook
Forecast
Current Conditions
Air Quality
Safety
Weather Alerts
Climate Advisory: Coos County
Climate Verdict
Coos County has a cool, averaging 40.0°F annually, moderately wet with 47.9 inches of annual precipitation, rare extreme heat with only 1.7363636363636366 days above 90°F annually, heavy winter snowfall averaging 118.8 inches per year. This climate profile shapes everything from energy costs to outdoor recreation opportunities.
Seasonal Breakdown
Winters are very cold — January averages 13.8°F. summers are pleasantly cool with July averaging 64.3°F. Residents experience a substantial 51°F difference between winter and summer.
Outdoor & Gardening Guidance
Winter sports enthusiasts benefit from reliable snow cover for 3-4 months annually.
Regional Context
Coos County is 5.4°F cooler than the New Hampshire statewide average of 45.4°F.
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 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.