Will Pipes Freeze in Shelby County, IA? 77 nights a Year
Freeze nights in Shelby County
In a normal year Shelby County, IA gets 77 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 81% of US counties.
Risk level: Severe. The risk season runs October to April, worst in January.
It depends where the pipe is
| Pipe | Freezes near | Nights a year |
|---|---|---|
| Outdoor spigot, open crawlspace | 32°F | 149 nights |
| Bare pipe in garage, attic or outside wall | 20°F | 77 nights |
| Insulated pipe in unheated space | 10°F | 38 nights |
| Inside the heated house | 0°F | 16 nights |
Foam-sleeving a bare pipe in unheated space takes it from 77 nights of risk to 38 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 10/09, last around 04/27. For 20°F: 11/05 to 03/31.
How cold Shelby County nights get
Average winter (Dec-Feb) low: 13°F; the coldest month, January, averages 10°F overnight. 8 months normally bring at least one night below 32°F (Jan, Feb, Mar, Apr, May, Oct, Nov, Dec). Nights below 10°F, cold enough to freeze insulated pipe in an unheated space, come in January, February, March, November, December: 38 nights a year, and 16 nights below zero.
| Jan | Feb | Mar | Apr | May | Jun | Jul | Aug | Sep | Oct | Nov | Dec |
|---|---|---|---|---|---|---|---|---|---|---|---|
| 10°F | 14°F | 25°F | 36°F | 49°F | 60°F | 64°F | 61°F | 52°F | 39°F | 26°F | 16°F |
Shelby County next to its neighbours
Audubon County, IA, 34 km east, gets 85 nights below 20°F to Shelby County's 77 nights. Crawford County, IA, 41 km north, gets 76 nights.
| County | Distance | Below 32°F | Below 20°F | Jan low |
|---|---|---|---|---|
| Shelby County, IA | - | 149 nights | 77 nights | 10°F |
| Audubon County, IA | 34 km east | 160 nights | 85 nights | 9°F |
| Crawford County, IA | 41 km north | 149 nights | 76 nights | 10°F |
| Pottawattamie County, IA | 42 km southwest | 146 nights | 73 nights | 12°F |
| Harrison County, IA | 43 km west | 154 nights | 81 nights | 10°F |
| Cass County, IA | 50 km southeast | 152 nights | 79 nights | 10°F |
| Carroll County, IA | 54 km northeast | 153 nights | 80 nights | 10°F |
Shelby County within IA
Shelby County ranks 48 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 1,205 ft, Shelby County sits 115 ft above 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.
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 Harlan, IA, 4 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.