Will Pipes Freeze in Warren County, IL? 57 nights a Year
Freeze nights in Warren County
In a normal year Warren County, IL gets 57 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 70% 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 | 132 nights |
| Bare pipe in garage, attic or outside wall | 20°F | 57 nights |
| Insulated pipe in unheated space | 10°F | 28 nights |
| Inside the heated house | 0°F | 10 nights |
Foam-sleeving a bare pipe in unheated space takes it from 57 nights of risk to 28 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 10/15, last around 04/22. For 20°F: 11/14 to 03/21.
How cold Warren County nights get
Average winter (Dec-Feb) low: 18°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: 28 nights a year, and 10 nights below zero.
| Jan | Feb | Mar | Apr | May | Jun | Jul | Aug | Sep | Oct | Nov | Dec |
|---|---|---|---|---|---|---|---|---|---|---|---|
| 14°F | 18°F | 29°F | 40°F | 51°F | 61°F | 64°F | 62°F | 54°F | 42°F | 30°F | 20°F |
Warren County next to its neighbours
Knox County, IL, 35 km east, gets 59 nights below 20°F to Warren County's 57 nights. Henderson County, IL, 27 km west, gets 52 nights.
| County | Distance | Below 32°F | Below 20°F | Jan low |
|---|---|---|---|---|
| Warren County, IL | - | 132 nights | 57 nights | 14°F |
| Henderson County, IL | 27 km west | 121 nights | 52 nights | 16°F |
| Knox County, IL | 35 km east | 135 nights | 59 nights | 14°F |
| Mercer County, IL | 41 km north | 138 nights | 62 nights | 13°F |
| McDonough County, IL | 44 km south | 134 nights | 58 nights | 15°F |
| Des Moines County, IA | 48 km west | 121 nights | 52 nights | 16°F |
| Fulton County, IL | 55 km southeast | 134 nights | 56 nights | 15°F |
Warren County within IL
Warren County ranks 20 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 770 ft, Warren County sits 138 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.
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 Monmouth, IL, 11 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.