Will Pipes Freeze in Waukesha County, WI? 71 nights a Year
Freeze nights in Waukesha County
In a normal year Waukesha County, WI gets 71 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 77% 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 | 146 nights |
| Bare pipe in garage, attic or outside wall | 20°F | 71 nights |
| Insulated pipe in unheated space | 10°F | 36 nights |
| Inside the heated house | 0°F | 14 nights |
Foam-sleeving a bare pipe in unheated space takes it from 71 nights of risk to 36 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 10/13, last around 05/01. For 20°F: 11/14 to 03/29.
How cold Waukesha County nights get
Average winter (Dec-Feb) low: 15°F; the coldest month, January, averages 12°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: 36 nights a year, and 14 nights below zero.
| Jan | Feb | Mar | Apr | May | Jun | Jul | Aug | Sep | Oct | Nov | Dec |
|---|---|---|---|---|---|---|---|---|---|---|---|
| 12°F | 15°F | 24°F | 35°F | 46°F | 56°F | 61°F | 59°F | 51°F | 40°F | 28°F | 18°F |
Waukesha County next to its neighbours
Jefferson County, WI, 38 km west, gets 73 nights below 20°F to Waukesha County's 71 nights. Milwaukee County, WI, 38 km east, gets 57 nights.
| County | Distance | Below 32°F | Below 20°F | Jan low |
|---|---|---|---|---|
| Waukesha County, WI | - | 146 nights | 71 nights | 12°F |
| Milwaukee County, WI | 38 km east | 125 nights | 57 nights | 16°F |
| Jefferson County, WI | 38 km west | 144 nights | 73 nights | 11°F |
| Washington County, WI | 42 km north | 157 nights | 79 nights | 10°F |
| Walworth County, WI | 43 km southwest | 141 nights | 61 nights | 14°F |
| Racine County, WI | 51 km southeast | 124 nights | 55 nights | 16°F |
| Dodge County, WI | 56 km northwest | 154 nights | 81 nights | 9°F |
Waukesha County within WI
Waukesha County ranks 64 of 72 WI counties for nights below 20°F. The most is Vilas County, WI at 116 nights, with a 4°F average winter low. The fewest is Racine County, WI: 55 nights, winter lows near 19°F. At 995 ft, Waukesha County sits close to the state's median county elevation of 995 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 Waukesha Wastewater Plant, WI, 5 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.