Ice dam risk in Plainfield, NJ
Will your roof get ice dams in Plainfield, NJ?
6.7 dam days a winter
Moderate risk. On an ordinary house in Plainfield, conditions for an ice dam come on about 6.7 days in a normal winter, mostly in February and January.
Plainfield averages 21 inches of snow a year and about 31 days with snow on the ground. Most of it comes and goes within a few days. The conditions that make a dam need all three at once: snow, cold at the eave and heat above it.
What your attic does to that number in Plainfield
| Attic | Dam days | Risk |
|---|---|---|
| Air-sealed and well insulated | 5.2 | Moderate |
| Typical, some insulation, not air-sealed | 6.7 | Moderate |
| Older or poorly insulated, warm attic | 8.6 | Moderate |
The attic matters less in Plainfield than in colder towns: there are only 1.5 days a winter between a typical attic and a sealed one.
Preventing ice dams on a Plainfield roof
- Rake the bottom three or four feet of roof after any storm that leaves more than about six inches, from the ground with a roof rake.
More on when a roof rake is worth it.
Plainfield winter, month by month
| Month | Snow (in) | Days on ground | Dam days |
|---|---|---|---|
| January | 5.1 | 9.7 | 2.5 |
| February | 8.3 | 11.6 | 2.6 |
| March | 5.3 | 5.2 | 0.7 |
| April | 0.1 | 0.2 | 0.0 |
| November | 0.2 | 0.1 | 0.0 |
| December | 2.4 | 4.4 | 0.9 |
Plainfield next to nearby towns
Plainfield ranks 17 of 116 New Jersey cities here for ice-dam days, behind Hopatcong at 14.7 days.
- North Plainfield, NJ 1 mi, 6.7 days
- South Plainfield, NJ 3 mi, 5.8 days
- Westfield, NJ 5 mi, 7.0 days
- Middlesex, NJ 5 mi, 5.8 days
- Metuchen, NJ 6 mi, 5.8 days
Where these numbers come from
NOAA 1991–2020 climate normals from Plainfield, 1.1 miles from Plainfield. A dam day is a day with snow on the roof and freezing at the eave while heat or sun melts the snow above it. This describes a normal winter, not this one.
- Snow-on-the-ground counts come from a second, nearby station, because the closest one does not record them.