New Hampshire cold wave risk
Coos County has the highest cold wave risk in New Hampshire, scoring 87.4 out of 100 — rated "Relatively Moderate" by FEMA's National Risk Index.
| # | County | NRI score | Rating |
|---|---|---|---|
| 1 | Coos County | 87.4 | Relatively Moderate |
| 2 | Hillsborough County | 66.2 | Relatively Moderate |
| 3 | Rockingham County | 57.4 | Relatively Low |
| 4 | Grafton County | 54.1 | Relatively Low |
| 5 | Merrimack County | 53.8 | Relatively Low |
| 6 | Cheshire County | 51.4 | Relatively Low |
| 7 | Carroll County | 44 | Relatively Low |
| 8 | Strafford County | 41.8 | Relatively Low |
| 9 | Sullivan County | 35.4 | Relatively Low |
| 10 | Belknap County | 32.5 | Relatively Low |
Source: FEMA National Risk Index v1.20.0, December 2025. Scores are 0–100 percentile rankings among all US counties. See the methodology page for definitions. Download the full CSV for all counties.
Cold Wave risk nationally:
Other hazard risks in New Hampshire:
Frequently asked questions
What is the highest cold wave risk county in New Hampshire?
Coos County, NH has the highest cold wave risk in New Hampshire, with a FEMA National Risk Index score of 87.4 out of 100 (rated "Relatively Moderate").
What causes cold wave risk in New Hampshire?
Cold wave risk captures expected losses from extended periods of extreme cold, including wind chill. The northern Plains, Great Lakes, and interior New England see the most severe and frequent cold events. Cold extremes cause significant excess mortality, especially among unhoused populations, the elderly, and those with inadequate heating or insulation. Cold and wind chill events are reported at forecast-zone level in NOAA Storm Events and are not included in county-level counts.