Will Pipes Freeze in St. Clair County, IL? 28 nights a Year
Freeze nights in St. Clair County
In a normal year St. Clair County, IL gets 28 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 44% of US counties.
Risk level: Regular. 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 | 94 nights |
| Bare pipe in garage, attic or outside wall | 20°F | 28 nights |
| Insulated pipe in unheated space | 10°F | 8 nights |
| Inside the heated house | 0°F | 1 night |
Foam-sleeving a bare pipe in unheated space takes it from 28 nights of risk to 8 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 04/12. For 20°F: 11/22 to 03/09.
How cold St. Clair County nights get
Average winter (Dec-Feb) low: 27°F; the coldest month, January, averages 24°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, December: 8 nights a year, and 1 night below zero.
| Jan | Feb | Mar | Apr | May | Jun | Jul | Aug | Sep | Oct | Nov | Dec |
|---|---|---|---|---|---|---|---|---|---|---|---|
| 24°F | 28°F | 36°F | 46°F | 56°F | 65°F | 68°F | 66°F | 57°F | 47°F | 37°F | 28°F |
St. Clair County next to its neighbours
Monroe County, IL, 31 km southwest, gets 33 nights below 20°F to St. Clair County's 28 nights. St. Louis city, MO, 33 km northwest, gets 26 nights.
| County | Distance | Below 32°F | Below 20°F | Jan low |
|---|---|---|---|---|
| St. Clair County, IL | - | 94 nights | 28 nights | 24°F |
| Monroe County, IL | 31 km southwest | 102 nights | 33 nights | 23°F |
| St. Louis city, MO | 33 km northwest | 83 nights | 26 nights | 24°F |
| Madison County, IL | 40 km north | 86 nights | 28 nights | 23°F |
| Clinton County, IL | 46 km east | 100 nights | 35 nights | 22°F |
| Washington County, IL | 46 km east | 95 nights | 30 nights | 21°F |
| Randolph County, IL | 47 km south | 106 nights | 33 nights | 22°F |
St. Clair County within IL
St. Clair County ranks 94 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 495 ft, St. Clair County sits 137 ft below the state's median county elevation of 632 ft.
What to do here
- Insulate every pipe in unheated space before the season starts.
- Heat tape on the runs you cannot insulate well.
- Shut off and drain outdoor spigots for the season.
When to have the house ready: when freeze season starts.
Where this comes from
NOAA 1991-2020 climate normals, blended from 3 nearby stations and adjusted for elevation; closest is Belleville Siu Rsch, IL, 9 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.