Will Pipes Freeze in Allegheny County, PA? 34 nights a Year
Freeze nights in Allegheny County
In a normal year Allegheny County, PA gets 34 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 50% of US counties.
Risk level: Regular. The risk season runs November to March, worst in January.
It depends where the pipe is
| Pipe | Freezes near | Nights a year |
|---|---|---|
| Outdoor spigot, open crawlspace | 32°F | 105 nights |
| Bare pipe in garage, attic or outside wall | 20°F | 34 nights |
| Insulated pipe in unheated space | 10°F | 11 nights |
| Inside the heated house | 0°F | 2 nights |
Foam-sleeving a bare pipe in unheated space takes it from 34 nights of risk to 11 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 10/27, last around 04/24. For 20°F: 11/28 to 03/19.
How cold Allegheny County nights get
Average winter (Dec-Feb) low: 23°F; the coldest month, January, averages 21°F overnight. 7 months normally bring at least one night below 32°F (Jan, Feb, Mar, Apr, Oct, Nov, Dec). Nights below 10°F, cold enough to freeze insulated pipe in an unheated space, come in January, February, March, December: 11 nights a year, and 2 nights below zero.
| Jan | Feb | Mar | Apr | May | Jun | Jul | Aug | Sep | Oct | Nov | Dec |
|---|---|---|---|---|---|---|---|---|---|---|---|
| 21°F | 22°F | 29°F | 39°F | 50°F | 59°F | 63°F | 62°F | 55°F | 44°F | 33°F | 26°F |
Allegheny County next to its neighbours
Washington County, PA, 38 km southwest, gets 48 nights below 20°F to Allegheny County's 34 nights.
| County | Distance | Below 32°F | Below 20°F | Jan low |
|---|---|---|---|---|
| Allegheny County, PA | - | 105 nights | 34 nights | 21°F |
| Washington County, PA | 38 km southwest | 121 nights | 48 nights | 20°F |
| Beaver County, PA | 39 km northwest | 121 nights | 39 nights | 20°F |
| Westmoreland County, PA | 47 km east | 137 nights | 53 nights | 19°F |
| Butler County, PA | 50 km north | 139 nights | 54 nights | 17°F |
| Hancock County, WV | 50 km west | 116 nights | 39 nights | 20°F |
| Brooke County, WV | 55 km southwest | 111 nights | 38 nights | 21°F |
Allegheny County within PA
Allegheny County ranks 61 of 67 PA counties for nights below 20°F. The most is Susquehanna County, PA at 80 nights, with a 15°F average winter low. The fewest is Delaware County, PA: 15 nights, winter lows near 28°F. At 946 ft, Allegheny County sits 196 ft below the state's median county elevation of 1,141 ft.
What to do here
- Insulate every pipe in unheated space before the season starts.
- Heat tape on the runs you cannot insulate well.
- Shut off and drain outdoor spigots for the season.
Why 20°F is the line for a garage pipe: how cold before pipes freeze.
Where this comes from
NOAA 1991-2020 climate normals, blended from 3 nearby stations and adjusted for elevation; closest is Emsworth L/d Ohio Rvr, PA, 10 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.