Will Pipes Freeze in Johnson County, WY? 99 nights a Year
Freeze nights in Johnson County
In a normal year Johnson County, WY gets 99 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 91% of US counties.
Risk level: Severe. The risk season runs October to April, worst in December.
It depends where the pipe is
| Pipe | Freezes near | Nights a year |
|---|---|---|
| Outdoor spigot, open crawlspace | 32°F | 190 nights |
| Bare pipe in garage, attic or outside wall | 20°F | 99 nights |
| Insulated pipe in unheated space | 10°F | 46 nights |
| Inside the heated house | 0°F | 19 nights |
Foam-sleeving a bare pipe in unheated space takes it from 99 nights of risk to 46 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 09/21, last around 05/19. For 20°F: 10/19 to 04/16.
How cold Johnson County nights get
Average winter (Dec-Feb) low: 12°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, April, October, November, December: 46 nights a year, and 19 nights below zero.
| Jan | Feb | Mar | Apr | May | Jun | Jul | Aug | Sep | Oct | Nov | Dec |
|---|---|---|---|---|---|---|---|---|---|---|---|
| 11°F | 14°F | 22°F | 29°F | 39°F | 48°F | 54°F | 52°F | 43°F | 30°F | 20°F | 12°F |
Johnson County next to its neighbours
Washakie County, WY, 88 km west, gets 107 nights below 20°F to Johnson County's 99 nights. Sheridan County, WY, 85 km north, gets 93 nights.
| County | Distance | Below 32°F | Below 20°F | Jan low |
|---|---|---|---|---|
| Johnson County, WY | - | 190 nights | 99 nights | 11°F |
| Sheridan County, WY | 85 km north | 185 nights | 93 nights | 13°F |
| Campbell County, WY | 87 km east | 177 nights | 84 nights | 15°F |
| Washakie County, WY | 88 km west | 189 nights | 107 nights | 5°F |
| Natrona County, WY | 119 km south | 195 nights | 104 nights | 11°F |
| Big Horn County, WY | 124 km northwest | 183 nights | 109 nights | 5°F |
| Converse County, WY | 146 km southeast | 182 nights | 92 nights | 13°F |
Johnson County within WY
Johnson County ranks 15 of 23 WY counties for nights below 20°F. The most is Sublette County, WY at 165 nights, with a 1°F average winter low. The fewest is Platte County, WY: 69 nights, winter lows near 16°F. At 4,677 ft, Johnson County sits 620 ft below the state's median county elevation of 5,297 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.
Interior pipes have a threshold too: the four freeze points.
Where this comes from
NOAA 1991-2020 climate normals, blended from 3 nearby stations and adjusted for elevation; closest is Billy Creek, WY, 15 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.