Will Pipes Freeze in Cass County, IL? 49 nights a Year
Freeze nights in Cass County
In a normal year Cass County, IL gets 49 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 63% 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 | 124 nights |
| Bare pipe in garage, attic or outside wall | 20°F | 49 nights |
| Insulated pipe in unheated space | 10°F | 20 nights |
| Inside the heated house | 0°F | 7 nights |
Foam-sleeving a bare pipe in unheated space takes it from 49 nights of risk to 20 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 10/17, last around 04/19. For 20°F: 11/20 to 03/18.
How cold Cass County nights get
Average winter (Dec-Feb) low: 21°F; the coldest month, January, averages 18°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, December: 20 nights a year, and 7 nights below zero.
| Jan | Feb | Mar | Apr | May | Jun | Jul | Aug | Sep | Oct | Nov | Dec |
|---|---|---|---|---|---|---|---|---|---|---|---|
| 18°F | 21°F | 30°F | 41°F | 52°F | 61°F | 65°F | 63°F | 54°F | 43°F | 32°F | 23°F |
Cass County next to its neighbours
Mason County, IL, 41 km northeast, gets 51 nights below 20°F to Cass County's 49 nights. Menard County, IL, 39 km east, gets 44 nights.
| County | Distance | Below 32°F | Below 20°F | Jan low |
|---|---|---|---|---|
| Cass County, IL | - | 124 nights | 49 nights | 18°F |
| Morgan County, IL | 28 km south | 125 nights | 49 nights | 18°F |
| Schuyler County, IL | 38 km northwest | 121 nights | 49 nights | 17°F |
| Menard County, IL | 39 km east | 121 nights | 44 nights | 17°F |
| Mason County, IL | 41 km northeast | 128 nights | 51 nights | 17°F |
| Scott County, IL | 42 km southwest | 122 nights | 50 nights | 18°F |
| Brown County, IL | 43 km west | 124 nights | 49 nights | 17°F |
Cass County within IL
Cass County ranks 44 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 629 ft, Cass 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 Jacksonville (2 mi E), IL, 26 km away (fair 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.