Will Pipes Freeze in Story County, IA? 75 nights a Year
Freeze nights in Story County
In a normal year Story County, IA gets 75 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 80% 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 | 150 nights |
| Bare pipe in garage, attic or outside wall | 20°F | 75 nights |
| Insulated pipe in unheated space | 10°F | 39 nights |
| Inside the heated house | 0°F | 18 nights |
Foam-sleeving a bare pipe in unheated space takes it from 75 nights of risk to 39 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 04/24. For 20°F: 11/09 to 03/26.
How cold Story County nights get
Average winter (Dec-Feb) low: 14°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: 39 nights a year, and 18 nights below zero.
| Jan | Feb | Mar | Apr | May | Jun | Jul | Aug | Sep | Oct | Nov | Dec |
|---|---|---|---|---|---|---|---|---|---|---|---|
| 10°F | 14°F | 26°F | 37°F | 49°F | 60°F | 63°F | 61°F | 51°F | 39°F | 27°F | 16°F |
Story County next to its neighbours
Boone County, IA, 39 km west, gets 76 nights below 20°F to Story County's 75 nights. Polk County, IA, 40 km south, gets 69 nights.
| County | Distance | Below 32°F | Below 20°F | Jan low |
|---|---|---|---|---|
| Story County, IA | - | 150 nights | 75 nights | 10°F |
| Boone County, IA | 39 km west | 151 nights | 76 nights | 10°F |
| Marshall County, IA | 40 km east | 151 nights | 76 nights | 10°F |
| Polk County, IA | 40 km south | 142 nights | 69 nights | 12°F |
| Hardin County, IA | 43 km northeast | 155 nights | 80 nights | 8°F |
| Hamilton County, IA | 44 km northwest | 160 nights | 84 nights | 7°F |
| Jasper County, IA | 52 km southeast | 142 nights | 71 nights | 11°F |
Story County within IA
Story County ranks 55 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 983 ft, Story County sits 107 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.
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 Colo, IA, 12 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.