Will Pipes Freeze in Jefferson County, IL? 37 nights a Year
Freeze nights in Jefferson County
In a normal year Jefferson County, IL gets 37 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 53% 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 | 108 nights |
| Bare pipe in garage, attic or outside wall | 20°F | 37 nights |
| Insulated pipe in unheated space | 10°F | 12 nights |
| Inside the heated house | 0°F | 3 nights |
Foam-sleeving a bare pipe in unheated space takes it from 37 nights of risk to 12 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 04/11. For 20°F: 11/25 to 03/09.
How cold Jefferson County nights get
Average winter (Dec-Feb) low: 24°F; the coldest month, January, averages 22°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: 12 nights a year, and 3 nights below zero.
| Jan | Feb | Mar | Apr | May | Jun | Jul | Aug | Sep | Oct | Nov | Dec |
|---|---|---|---|---|---|---|---|---|---|---|---|
| 22°F | 25°F | 34°F | 44°F | 55°F | 64°F | 67°F | 65°F | 57°F | 45°F | 34°F | 26°F |
Jefferson County next to its neighbours
Franklin County, IL, 34 km south, gets 29 nights.
| County | Distance | Below 32°F | Below 20°F | Jan low |
|---|---|---|---|---|
| Jefferson County, IL | - | 108 nights | 37 nights | 22°F |
| Franklin County, IL | 34 km south | 95 nights | 29 nights | 24°F |
| Marion County, IL | 39 km north | 102 nights | 34 nights | 21°F |
| Hamilton County, IL | 41 km southeast | 110 nights | 37 nights | 22°F |
| Washington County, IL | 43 km west | 95 nights | 30 nights | 21°F |
| Wayne County, IL | 45 km east | 100 nights | 32 nights | 24°F |
| Perry County, IL | 46 km southwest | 96 nights | 29 nights | 23°F |
Jefferson County within IL
Jefferson County ranks 69 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 479 ft, Jefferson County sits 153 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.
What insulating actually removes here, and when heat tape is needed: insulate or heat tape?.
Where this comes from
NOAA 1991-2020 climate normals, blended from 3 nearby stations and adjusted for elevation; closest is Mount Vernon (3 mi NE), IL, 8 km away (close match). A normal year, not tonight's forecast: check the forecast low for the night itself. What a "fair" or "distant" station match means is in the method guide.