Will Pipes Freeze in Boone County, IL? 70 nights a Year
Freeze nights in Boone County
In a normal year Boone County, IL gets 70 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 77% 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 | 146 nights |
| Bare pipe in garage, attic or outside wall | 20°F | 70 nights |
| Insulated pipe in unheated space | 10°F | 35 nights |
| Inside the heated house | 0°F | 15 nights |
Foam-sleeving a bare pipe in unheated space takes it from 70 nights of risk to 35 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 10/12, last around 04/28. For 20°F: 11/15 to 03/27.
How cold Boone County nights get
Average winter (Dec-Feb) low: 15°F; the coldest month, January, averages 12°F overnight. 8 months normally bring at least one night below 32°F (Jan, Feb, Mar, Apr, May, Oct, Nov, Dec). Nights below 10°F, cold enough to freeze insulated pipe in an unheated space, come in January, February, March, November, December: 35 nights a year, and 15 nights below zero.
| Jan | Feb | Mar | Apr | May | Jun | Jul | Aug | Sep | Oct | Nov | Dec |
|---|---|---|---|---|---|---|---|---|---|---|---|
| 12°F | 15°F | 25°F | 36°F | 47°F | 57°F | 61°F | 59°F | 51°F | 39°F | 29°F | 18°F |
Boone County next to its neighbours
Rock County, WI, 44 km northwest, gets 71 nights below 20°F to Boone County's 70 nights. Winnebago County, IL, 28 km west, gets 65 nights.
| County | Distance | Below 32°F | Below 20°F | Jan low |
|---|---|---|---|---|
| Boone County, IL | - | 146 nights | 70 nights | 12°F |
| Winnebago County, IL | 28 km west | 140 nights | 65 nights | 13°F |
| McHenry County, IL | 31 km east | 139 nights | 62 nights | 14°F |
| Rock County, WI | 44 km northwest | 147 nights | 71 nights | 11°F |
| Walworth County, WI | 45 km northeast | 141 nights | 61 nights | 14°F |
| DeKalb County, IL | 47 km south | 141 nights | 64 nights | 13°F |
| Ogle County, IL | 51 km southwest | 140 nights | 65 nights | 13°F |
Boone County within IL
Boone County ranks 4 of 102 IL counties for nights below 20°F. The most is Jo Daviess County, IL at 76 nights, with a 14°F average winter low. The fewest is Alexander County, IL: 21 nights, winter lows near 29°F. At 838 ft, Boone County sits 206 ft above the state's median county elevation of 632 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.
Interior pipes have a threshold too: the four freeze points.
Where this comes from
NOAA 1991-2020 climate normals, blended from 3 nearby stations and adjusted for elevation; closest is Marengo, IL, 19 km away (close match). A normal year, not tonight's forecast: check the forecast low for the night itself. Why elevation is part of the blend: how county numbers are made.