Will Pipes Freeze in Jefferson County, IA? 54 nights a Year
Freeze nights in Jefferson County
In a normal year Jefferson County, IA gets 54 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 April, worst in January.
It depends where the pipe is
| Pipe | Freezes near | Nights a year |
|---|---|---|
| Outdoor spigot, open crawlspace | 32°F | 127 nights |
| Bare pipe in garage, attic or outside wall | 20°F | 54 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 54 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 10/12, last around 04/27. For 20°F: 11/09 to 03/26.
How cold Jefferson County nights get
Average winter (Dec-Feb) low: 17°F; the coldest month, January, averages 14°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 |
|---|---|---|---|---|---|---|---|---|---|---|---|
| 14°F | 18°F | 28°F | 39°F | 50°F | 60°F | 64°F | 61°F | 53°F | 41°F | 30°F | 20°F |
Jefferson County next to its neighbours
Henry County, IA, 35 km east, gets 58 nights below 20°F to Jefferson County's 54 nights.
| County | Distance | Below 32°F | Below 20°F | Jan low |
|---|---|---|---|---|
| Jefferson County, IA | - | 127 nights | 54 nights | 14°F |
| Van Buren County, IA | 28 km south | 128 nights | 55 nights | 14°F |
| Henry County, IA | 35 km east | 130 nights | 58 nights | 13°F |
| Wapello County, IA | 37 km west | 131 nights | 59 nights | 14°F |
| Keokuk County, IA | 40 km northwest | 142 nights | 69 nights | 12°F |
| Washington County, IA | 41 km northeast | 139 nights | 65 nights | 12°F |
| Davis County, IA | 47 km southwest | 128 nights | 59 nights | 15°F |
Jefferson County within IA
Jefferson County ranks 98 of 99 IA counties for nights below 20°F. The most is Osceola County, IA at 99 nights, with a 8°F average winter low. The fewest is Des Moines County, IA: 52 nights, winter lows near 19°F. At 776 ft, Jefferson County sits 314 ft below the state's median county elevation of 1,090 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 Fairfield, IA, 2 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.