Will Pipes Freeze in Knox County, IL? 59 nights a Year
Freeze nights in Knox County
In a normal year Knox County, IL gets 59 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 71% 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 | 135 nights |
| Bare pipe in garage, attic or outside wall | 20°F | 59 nights |
| Insulated pipe in unheated space | 10°F | 29 nights |
| Inside the heated house | 0°F | 12 nights |
Foam-sleeving a bare pipe in unheated space takes it from 59 nights of risk to 29 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 10/20, last around 04/21. For 20°F: 11/19 to 03/19.
How cold Knox County nights get
Average winter (Dec-Feb) low: 17°F; the coldest month, January, averages 14°F overnight. 7 months normally bring at least one night below 32°F (Jan, Feb, Mar, Apr, Oct, Nov, Dec). Nights below 10°F, cold enough to freeze insulated pipe in an unheated space, come in January, February, March, November, December: 29 nights a year, and 12 nights below zero.
| Jan | Feb | Mar | Apr | May | Jun | Jul | Aug | Sep | Oct | Nov | Dec |
|---|---|---|---|---|---|---|---|---|---|---|---|
| 14°F | 18°F | 28°F | 39°F | 51°F | 61°F | 65°F | 62°F | 54°F | 42°F | 30°F | 20°F |
Knox County next to its neighbours
Stark County, IL, 40 km northeast, gets 64 nights below 20°F to Knox County's 59 nights. Warren County, IL, 35 km west, gets 57 nights.
| County | Distance | Below 32°F | Below 20°F | Jan low |
|---|---|---|---|---|
| Knox County, IL | - | 135 nights | 59 nights | 14°F |
| Warren County, IL | 35 km west | 132 nights | 57 nights | 14°F |
| Stark County, IL | 40 km northeast | 141 nights | 64 nights | 14°F |
| Peoria County, IL | 41 km southeast | 127 nights | 54 nights | 17°F |
| Henry County, IL | 47 km north | 131 nights | 58 nights | 14°F |
| Fulton County, IL | 52 km south | 134 nights | 56 nights | 15°F |
| Mercer County, IL | 54 km northwest | 138 nights | 62 nights | 13°F |
Knox County within IL
Knox County ranks 14 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 650 ft, Knox County sits close to 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.
The dates to be done by: when freeze season starts and ends.
Where this comes from
NOAA 1991-2020 climate normals, blended from 3 nearby stations and adjusted for elevation; closest is Knoxville, IL, 7 km away (close match). A normal year, not tonight's forecast: check the forecast low for the night itself. How a county figure is built from stations: how the numbers are made.