Will Pipes Freeze in Hillsborough County, NH? 72 nights a Year
Freeze nights in Hillsborough County
In a normal year Hillsborough County, NH gets 72 nights at or below 20°F, the point where bare pipes in a garage, attic or outside wall start to freeze. That is more than 78% of US counties.
Risk level: Severe. The risk season runs November to April, worst in January.
It depends where the pipe is
| Pipe | Freezes near | Nights a year |
|---|---|---|
| Outdoor spigot, open crawlspace | 32°F | 161 nights |
| Bare pipe in garage, attic or outside wall | 20°F | 72 nights |
| Insulated pipe in unheated space | 10°F | 32 nights |
| Inside the heated house | 0°F | 9 nights |
Foam-sleeving a bare pipe in unheated space takes it from 72 nights of risk to 32 nights. A 12 ft heat-tape kit runs $17 to $37; an average burst-pipe repair is about $500.
Month by month
Nights at or below 20°F in a normal year.
First 32°F night is usually around 10/08, last around 05/02. For 20°F: 11/18 to 03/31.
How cold Hillsborough County nights get
Average winter (Dec-Feb) low: 16°F; the coldest month, January, averages 14°F overnight. 9 months normally bring at least one night below 32°F (Jan, Feb, Mar, Apr, May, Sep, Oct, Nov, Dec). Nights below 10°F, cold enough to freeze insulated pipe in an unheated space, come in January, February, March, December: 32 nights a year, and 9 nights below zero.
| Jan | Feb | Mar | Apr | May | Jun | Jul | Aug | Sep | Oct | Nov | Dec |
|---|---|---|---|---|---|---|---|---|---|---|---|
| 14°F | 15°F | 23°F | 33°F | 44°F | 54°F | 59°F | 57°F | 50°F | 38°F | 29°F | 20°F |
Hillsborough County next to its neighbours
Cheshire County, NH, 43 km west, gets 77 nights below 20°F to Hillsborough County's 72 nights. Rockingham County, NH, 52 km east, gets 65 nights.
| County | Distance | Below 32°F | Below 20°F | Jan low |
|---|---|---|---|---|
| Hillsborough County, NH | - | 161 nights | 72 nights | 14°F |
| Cheshire County, NH | 43 km west | 169 nights | 77 nights | 11°F |
| Merrimack County, NH | 43 km north | 172 nights | 80 nights | 12°F |
| Rockingham County, NH | 52 km east | 154 nights | 65 nights | 14°F |
| Middlesex County, MA | 55 km southeast | 143 nights | 60 nights | 16°F |
| Sullivan County, NH | 64 km northwest | 185 nights | 94 nights | 9°F |
| Worcester County, MA | 69 km south | 137 nights | 58 nights | 16°F |
Hillsborough County within NH
Hillsborough County ranks 7 of 10 NH counties for nights below 20°F. The most is Coos County, NH at 110 nights, with a 6°F average winter low. The fewest is Strafford County, NH: 63 nights, winter lows near 18°F. At 710 ft, Hillsborough County sits close to the state's median county elevation of 712 ft.
What to do here
- Treat it as a building fix, not a night-of routine: insulate, heat tape, seal crawlspace vents.
- An automatic leak shutoff pays for itself if one burst is avoided.
- Know where the main shutoff is before the first hard freeze.
At this many nights, foam alone is not the answer: insulate or heat tape?.
Where this comes from
NOAA 1991-2020 climate normals, blended from 3 nearby stations and adjusted for elevation; closest is Weare, NH, 19 km away (close match). A normal year, not tonight's forecast: check the forecast low for the night itself. What a "fair" or "distant" station match means is in the method guide.