Will Pipes Freeze in Montgomery County, MD? 21 nights a Year
Freeze nights in Montgomery County
In a normal year Montgomery County, MD gets 21 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 37% 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 | 87 nights |
| Bare pipe in garage, attic or outside wall | 20°F | 21 nights |
| Insulated pipe in unheated space | 10°F | 3 nights |
| Inside the heated house | 0°F | under 1 night |
Foam-sleeving a bare pipe in unheated space takes it from 21 nights of risk to 3 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 11/06, last around 04/01. For 20°F: 12/20 to 02/28.
How cold Montgomery County nights get
Average winter (Dec-Feb) low: 29°F; the coldest month, January, averages 27°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: 3 nights a year, and under 1 night below zero.
| Jan | Feb | Mar | Apr | May | Jun | Jul | Aug | Sep | Oct | Nov | Dec |
|---|---|---|---|---|---|---|---|---|---|---|---|
| 27°F | 28°F | 36°F | 45°F | 55°F | 63°F | 69°F | 67°F | 60°F | 48°F | 38°F | 31°F |
Montgomery County next to its neighbours
Fairfax city, VA, 33 km south, gets 24 nights below 20°F to Montgomery County's 21 nights. Howard County, MD, 27 km northeast, gets 20 nights.
| County | Distance | Below 32°F | Below 20°F | Jan low |
|---|---|---|---|---|
| Montgomery County, MD | - | 87 nights | 21 nights | 27°F |
| Howard County, MD | 27 km northeast | 87 nights | 20 nights | 26°F |
| Falls Church city, VA | 28 km south | 92 nights | 21 nights | 25°F |
| Arlington County, VA | 30 km south | 83 nights | 18 nights | 27°F |
| District of Columbia, DC | 31 km southeast | 80 nights | 16 nights | 28°F |
| Fairfax city, VA | 33 km south | 100 nights | 24 nights | 24°F |
| Fairfax County, VA | 35 km south | 99 nights | 24 nights | 24°F |
Montgomery County within MD
Montgomery County ranks 10 of 24 MD counties for nights below 20°F. The most is Garrett County, MD at 57 nights, with a 20°F average winter low. The fewest is Baltimore city, MD: 10 nights, winter lows near 32°F. At 477 ft, Montgomery County sits 340 ft above the state's median county elevation of 138 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.
What insulating actually removes here, and when heat tape is needed: insulate or heat tape?.
Where this comes from
NOAA 1991-2020 climate normals, blended from 3 nearby stations and adjusted for elevation; closest is Rockville (1 mi NE), MD, 6 km away (close match). A normal year, not tonight's forecast: check the forecast low for the night itself. What a "fair" or "distant" station match means is in the method guide.