Will Pipes Freeze in St. Charles County, MO? 37 nights a Year
Freeze nights in St. Charles County
In a normal year St. Charles County, MO gets 37 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 53% 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 | 104 nights |
| Bare pipe in garage, attic or outside wall | 20°F | 37 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 37 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 10/26, last around 04/09. For 20°F: 11/29 to 03/09.
How cold St. Charles County nights get
Average winter (Dec-Feb) low: 24°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, December: 11 nights a year, and 2 nights below zero.
| Jan | Feb | Mar | Apr | May | Jun | Jul | Aug | Sep | Oct | Nov | Dec |
|---|---|---|---|---|---|---|---|---|---|---|---|
| 21°F | 25°F | 33°F | 44°F | 54°F | 63°F | 68°F | 65°F | 57°F | 45°F | 35°F | 26°F |
St. Charles County next to its neighbours
Lincoln County, MO, 40 km northwest, gets 39 nights below 20°F to St. Charles County's 37 nights. St. Louis County, MO, 25 km southeast, gets 31 nights.
| County | Distance | Below 32°F | Below 20°F | Jan low |
|---|---|---|---|---|
| St. Charles County, MO | - | 104 nights | 37 nights | 21°F |
| St. Louis County, MO | 25 km southeast | 93 nights | 31 nights | 23°F |
| Lincoln County, MO | 40 km northwest | 108 nights | 39 nights | 20°F |
| St. Louis city, MO | 41 km southeast | 83 nights | 26 nights | 24°F |
| Warren County, MO | 42 km west | 112 nights | 41 nights | 20°F |
| Calhoun County, IL | 43 km north | 109 nights | 39 nights | 20°F |
| Jersey County, IL | 43 km northeast | 117 nights | 42 nights | 19°F |
St. Charles County within MO
St. Charles County ranks 70 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 564 ft, St. Charles County sits 278 ft below the state's median county elevation of 842 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 St Peters (2 mi SE), MO, 8 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.