Will Pipes Freeze in Jefferson County, CO? 105 nights a Year
Freeze nights in Jefferson County
In a normal year Jefferson County, CO gets 105 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 94% of US counties.
Risk level: Severe. The risk season runs October to May, worst in January.
It depends where the pipe is
| Pipe | Freezes near | Nights a year |
|---|---|---|
| Outdoor spigot, open crawlspace | 32°F | 208 nights |
| Bare pipe in garage, attic or outside wall | 20°F | 105 nights |
| Insulated pipe in unheated space | 10°F | 44 nights |
| Inside the heated house | 0°F | 13 nights |
Foam-sleeving a bare pipe in unheated space takes it from 105 nights of risk to 44 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 09/22, last around 05/23. For 20°F: 10/20 to 04/22.
How cold Jefferson County nights get
Average winter (Dec-Feb) low: 14°F; the coldest month, December, averages 13°F overnight. 10 months normally bring at least one night below 32°F (Jan, Feb, Mar, Apr, May, Jun, 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: 44 nights a year, and 13 nights below zero.
| Jan | Feb | Mar | Apr | May | Jun | Jul | Aug | Sep | Oct | Nov | Dec |
|---|---|---|---|---|---|---|---|---|---|---|---|
| 14°F | 14°F | 22°F | 28°F | 37°F | 44°F | 51°F | 49°F | 41°F | 30°F | 21°F | 13°F |
Jefferson County next to its neighbours
Clear Creek County, CO, 38 km west, gets 136 nights below 20°F to Jefferson County's 105 nights. Denver County, CO, 37 km northeast, gets 61 nights.
| County | Distance | Below 32°F | Below 20°F | Jan low |
|---|---|---|---|---|
| Jefferson County, CO | - | 208 nights | 105 nights | 14°F |
| Denver County, CO | 37 km northeast | 156 nights | 61 nights | 18°F |
| Clear Creek County, CO | 38 km west | 234 nights | 136 nights | 12°F |
| Douglas County, CO | 39 km southeast | 167 nights | 71 nights | 18°F |
| Gilpin County, CO | 40 km northwest | 235 nights | 126 nights | 13°F |
| Broomfield County, CO | 45 km north | 150 nights | 58 nights | 19°F |
| Boulder County, CO | 59 km north | 200 nights | 86 nights | 16°F |
Jefferson County within CO
Jefferson County ranks 28 of 64 CO counties for nights below 20°F. The most is Summit County, CO at 177 nights, with a 5°F average winter low. The fewest is Mesa County, CO: 44 nights, winter lows near 21°F. At 7,559 ft, Jefferson County sits 679 ft above the state's median county elevation of 6,880 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.
The dates to be done by: when freeze season starts and ends.
Where this comes from
NOAA 1991-2020 climate normals, blended from 3 nearby stations and adjusted for elevation; closest is Evergreen, CO, 9 km away (fair match). A normal year, not tonight's forecast: check the forecast low for the night itself. Why elevation is part of the blend: how county numbers are made.