Will Pipes Freeze in District of Columbia, DC? 16 nights a Year
Freeze nights in District of Columbia
In a normal year District of Columbia, DC gets 16 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 33% of US counties.
Risk level: Regular. The risk season runs December to March, worst in January.
It depends where the pipe is
| Pipe | Freezes near | Nights a year |
|---|---|---|
| Outdoor spigot, open crawlspace | 32°F | 80 nights |
| Bare pipe in garage, attic or outside wall | 20°F | 16 nights |
| Insulated pipe in unheated space | 10°F | 2 nights |
| Inside the heated house | 0°F | under 1 night |
Foam-sleeving a bare pipe in unheated space takes it from 16 nights of risk to 2 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 11/08, last around 03/29. For 20°F: 12/26 to 02/23.
How cold District of Columbia nights get
Average winter (Dec-Feb) low: 30°F; the coldest month, January, averages 28°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: 2 nights a year, and under 1 night below zero.
| Jan | Feb | Mar | Apr | May | Jun | Jul | Aug | Sep | Oct | Nov | Dec |
|---|---|---|---|---|---|---|---|---|---|---|---|
| 28°F | 30°F | 37°F | 47°F | 57°F | 66°F | 71°F | 69°F | 62°F | 50°F | 39°F | 32°F |
District of Columbia next to its neighbours
Arlington County, VA, 8 km west, gets 18 nights below 20°F to District of Columbia's 16 nights. Alexandria city, VA, 11 km southwest, gets 15 nights.
| County | Distance | Below 32°F | Below 20°F | Jan low |
|---|---|---|---|---|
| District of Columbia, DC | - | 80 nights | 16 nights | 28°F |
| Arlington County, VA | 8 km west | 83 nights | 18 nights | 27°F |
| Alexandria city, VA | 11 km southwest | 76 nights | 15 nights | 28°F |
| Falls Church city, VA | 14 km west | 92 nights | 21 nights | 25°F |
| Prince George's County, MD | 17 km southeast | 99 nights | 26 nights | 25°F |
| Fairfax County, VA | 24 km west | 99 nights | 24 nights | 24°F |
| Fairfax city, VA | 25 km west | 100 nights | 24 nights | 24°F |
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.
When to have the house ready: when freeze season starts.
Where this comes from
NOAA 1991-2020 climate normals, blended from 3 nearby stations and adjusted for elevation; closest is Natl Arboretum Dc, MD, 4 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.