Will Pipes Freeze in Johnson County, MO? 45 nights a Year
Freeze nights in Johnson County
In a normal year Johnson County, MO gets 45 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 61% of US counties.
Risk level: Severe. 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 | 118 nights |
| Bare pipe in garage, attic or outside wall | 20°F | 45 nights |
| Insulated pipe in unheated space | 10°F | 16 nights |
| Inside the heated house | 0°F | 4 nights |
Foam-sleeving a bare pipe in unheated space takes it from 45 nights of risk to 16 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 10/21, last around 04/14. For 20°F: 11/19 to 03/11.
How cold Johnson County nights get
Average winter (Dec-Feb) low: 21°F; the coldest month, January, averages 18°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: 16 nights a year, and 4 nights below zero.
| Jan | Feb | Mar | Apr | May | Jun | Jul | Aug | Sep | Oct | Nov | Dec |
|---|---|---|---|---|---|---|---|---|---|---|---|
| 18°F | 22°F | 32°F | 42°F | 53°F | 63°F | 67°F | 65°F | 56°F | 44°F | 33°F | 23°F |
Johnson County next to its neighbours
Ray County, MO, 65 km north, gets 57 nights below 20°F to Johnson County's 45 nights. Pettis County, MO, 46 km east, gets 42 nights.
| County | Distance | Below 32°F | Below 20°F | Jan low |
|---|---|---|---|---|
| Johnson County, MO | - | 118 nights | 45 nights | 18°F |
| Lafayette County, MO | 36 km north | 117 nights | 45 nights | 19°F |
| Henry County, MO | 40 km south | 117 nights | 45 nights | 19°F |
| Pettis County, MO | 46 km east | 114 nights | 42 nights | 20°F |
| Cass County, MO | 48 km west | 107 nights | 41 nights | 20°F |
| Jackson County, MO | 55 km northwest | 105 nights | 40 nights | 20°F |
| Ray County, MO | 65 km north | 129 nights | 57 nights | 16°F |
Johnson County within MO
Johnson County ranks 35 of 115 MO counties for nights below 20°F. The most is Caldwell County, MO at 65 nights, with a 19°F average winter low. The fewest is Pemiscot County, MO: 14 nights, winter lows near 31°F. At 794 ft, Johnson County sits close to the state's median county elevation of 842 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 Warrensburg (4 mi NW), MO, 5 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.