Will Pipes Freeze in LaSalle County, IL? 55 nights a Year
Freeze nights in LaSalle County
In a normal year LaSalle County, IL gets 55 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 68% of US counties.
Risk level: Severe. The risk season runs November to March, worst in January.
It depends where the pipe is
| Pipe | Freezes near | Nights a year |
|---|---|---|
| Outdoor spigot, open crawlspace | 32°F | 130 nights |
| Bare pipe in garage, attic or outside wall | 20°F | 55 nights |
| Insulated pipe in unheated space | 10°F | 25 nights |
| Inside the heated house | 0°F | 10 nights |
Foam-sleeving a bare pipe in unheated space takes it from 55 nights of risk to 25 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 10/22, last around 04/20. For 20°F: 11/22 to 03/19.
How cold LaSalle County nights get
Average winter (Dec-Feb) low: 18°F; the coldest month, January, averages 15°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: 25 nights a year, and 10 nights below zero.
| Jan | Feb | Mar | Apr | May | Jun | Jul | Aug | Sep | Oct | Nov | Dec |
|---|---|---|---|---|---|---|---|---|---|---|---|
| 15°F | 19°F | 29°F | 39°F | 51°F | 60°F | 64°F | 62°F | 54°F | 42°F | 31°F | 21°F |
LaSalle County next to its neighbours
Kendall County, IL, 47 km northeast, gets 59 nights below 20°F to LaSalle County's 55 nights. Putnam County, IL, 38 km southwest, gets 51 nights.
| County | Distance | Below 32°F | Below 20°F | Jan low |
|---|---|---|---|---|
| LaSalle County, IL | - | 130 nights | 55 nights | 15°F |
| Putnam County, IL | 38 km southwest | 126 nights | 51 nights | 16°F |
| Grundy County, IL | 41 km east | 129 nights | 55 nights | 16°F |
| Kendall County, IL | 47 km northeast | 136 nights | 59 nights | 15°F |
| Marshall County, IL | 52 km southwest | 122 nights | 47 nights | 18°F |
| Bureau County, IL | 54 km west | 128 nights | 55 nights | 14°F |
| Lee County, IL | 57 km northwest | 145 nights | 66 nights | 13°F |
LaSalle County within IL
LaSalle County ranks 26 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 475 ft, LaSalle County sits 156 ft below 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 Ottawa (5 mi SW), IL, 3 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.