Will Pipes Freeze in Clarke County, IA? 72 nights a Year
Freeze nights in Clarke County
In a normal year Clarke County, IA gets 72 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 78% 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 | 148 nights |
| Bare pipe in garage, attic or outside wall | 20°F | 72 nights |
| Insulated pipe in unheated space | 10°F | 35 nights |
| Inside the heated house | 0°F | 14 nights |
Foam-sleeving a bare pipe in unheated space takes it from 72 nights of risk to 35 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 04/29. For 20°F: 11/06 to 03/29.
How cold Clarke County nights get
Average winter (Dec-Feb) low: 15°F; the coldest month, January, averages 11°F overnight. 9 months normally bring at least one night below 32°F (Jan, Feb, Mar, Apr, May, Sep, Oct, Nov, Dec). Nights below 10°F, cold enough to freeze insulated pipe in an unheated space, come in January, February, March, November, December: 35 nights a year, and 14 nights below zero.
| Jan | Feb | Mar | Apr | May | Jun | Jul | Aug | Sep | Oct | Nov | Dec |
|---|---|---|---|---|---|---|---|---|---|---|---|
| 11°F | 15°F | 26°F | 37°F | 49°F | 60°F | 64°F | 61°F | 51°F | 39°F | 27°F | 17°F |
Clarke County next to its neighbours
Lucas County, IA, 38 km east, gets 79 nights below 20°F to Clarke County's 72 nights. Decatur County, IA, 33 km south, gets 66 nights.
| County | Distance | Below 32°F | Below 20°F | Jan low |
|---|---|---|---|---|
| Clarke County, IA | - | 148 nights | 72 nights | 11°F |
| Decatur County, IA | 33 km south | 138 nights | 66 nights | 14°F |
| Lucas County, IA | 38 km east | 153 nights | 79 nights | 11°F |
| Warren County, IA | 38 km northeast | 141 nights | 69 nights | 12°F |
| Union County, IA | 39 km west | 144 nights | 71 nights | 11°F |
| Madison County, IA | 39 km northwest | 145 nights | 73 nights | 10°F |
| Wayne County, IA | 50 km southeast | 141 nights | 69 nights | 13°F |
Clarke County within IA
Clarke County ranks 62 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 1,117 ft, Clarke County sits close to 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 Osceola, IA, 3 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.