Will Pipes Freeze in DeKalb County, IL? 64 nights a Year
Freeze nights in DeKalb County
In a normal year DeKalb County, IL gets 64 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 73% 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 | 141 nights |
| Bare pipe in garage, attic or outside wall | 20°F | 64 nights |
| Insulated pipe in unheated space | 10°F | 32 nights |
| Inside the heated house | 0°F | 13 nights |
Foam-sleeving a bare pipe in unheated space takes it from 64 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 10/18, last around 04/24. For 20°F: 11/18 to 03/22.
How cold DeKalb County nights get
Average winter (Dec-Feb) low: 16°F; the coldest month, January, averages 13°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: 32 nights a year, and 13 nights below zero.
| Jan | Feb | Mar | Apr | May | Jun | Jul | Aug | Sep | Oct | Nov | Dec |
|---|---|---|---|---|---|---|---|---|---|---|---|
| 13°F | 17°F | 27°F | 37°F | 49°F | 59°F | 63°F | 61°F | 53°F | 41°F | 29°F | 19°F |
DeKalb County next to its neighbours
Lee County, IL, 47 km west, gets 66 nights below 20°F to DeKalb County's 64 nights. Kane County, IL, 29 km east, gets 61 nights.
| County | Distance | Below 32°F | Below 20°F | Jan low |
|---|---|---|---|---|
| DeKalb County, IL | - | 141 nights | 64 nights | 13°F |
| Kane County, IL | 29 km east | 138 nights | 61 nights | 15°F |
| Kendall County, IL | 44 km southeast | 136 nights | 59 nights | 15°F |
| Lee County, IL | 47 km west | 145 nights | 66 nights | 13°F |
| Boone County, IL | 47 km north | 146 nights | 70 nights | 12°F |
| Ogle County, IL | 48 km west | 140 nights | 65 nights | 13°F |
| McHenry County, IL | 54 km northeast | 139 nights | 62 nights | 14°F |
DeKalb County within IL
DeKalb County ranks 10 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 861 ft, DeKalb County sits 230 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 De Kalb, IL, 4 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.