Will Pipes Freeze in Washtenaw County, MI? 66 nights a Year
Freeze nights in Washtenaw County
In a normal year Washtenaw County, MI gets 66 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 74% 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 | 66 nights |
| Insulated pipe in unheated space | 10°F | 28 nights |
| Inside the heated house | 0°F | 10 nights |
Foam-sleeving a bare pipe in unheated space takes it from 66 nights of risk to 28 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 10/04, last around 05/08. For 20°F: 11/10 to 04/02.
How cold Washtenaw County nights get
Average winter (Dec-Feb) low: 18°F; the coldest month, January, averages 15°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: 28 nights a year, and 10 nights below zero.
| Jan | Feb | Mar | Apr | May | Jun | Jul | Aug | Sep | Oct | Nov | Dec |
|---|---|---|---|---|---|---|---|---|---|---|---|
| 15°F | 16°F | 25°F | 35°F | 46°F | 55°F | 58°F | 57°F | 49°F | 38°F | 29°F | 22°F |
Washtenaw County next to its neighbours
Livingston County, MI, 39 km north, gets 73 nights below 20°F to Washtenaw County's 66 nights. Lenawee County, MI, 44 km southwest, gets 53 nights.
| County | Distance | Below 32°F | Below 20°F | Jan low |
|---|---|---|---|---|
| Washtenaw County, MI | - | 150 nights | 66 nights | 15°F |
| Livingston County, MI | 39 km north | 154 nights | 73 nights | 14°F |
| Lenawee County, MI | 44 km southwest | 135 nights | 53 nights | 17°F |
| Jackson County, MI | 48 km west | 137 nights | 57 nights | 17°F |
| Monroe County, MI | 48 km southeast | 129 nights | 52 nights | 18°F |
| Wayne County, MI | 48 km east | 131 nights | 51 nights | 18°F |
| Ingham County, MI | 58 km northwest | 144 nights | 62 nights | 17°F |
Washtenaw County within MI
Washtenaw County ranks 46 of 83 MI counties for nights below 20°F. The most is Iron County, MI at 120 nights, with a 3°F average winter low. The fewest is Allegan County, MI: 38 nights, winter lows near 24°F. At 961 ft, Washtenaw County sits 153 ft above the state's median county elevation of 808 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 Ann Arbor Municipal Airport, MI, 9 km away (close match). A normal year, not tonight's forecast: check the forecast low for the night itself. How a county figure is built from stations: how the numbers are made.