Ice dam risk in Quincy, IL
Will your roof get ice dams in Quincy, IL?
6.7 dam days a winter
Moderate risk. On an ordinary house in Quincy, conditions for an ice dam come on about 6.7 days in a normal winter, mostly in January and February.
Quincy averages 18 inches of snow a year and about 25 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 Quincy
| Attic | Dam days | Risk |
|---|---|---|
| Air-sealed and well insulated | 3.9 | Low |
| Typical, some insulation, not air-sealed | 6.7 | Moderate |
| Older or poorly insulated, warm attic | 10.3 | Moderate |
Sealing and insulating a typical attic takes out about 2.9 days a winter here. It drops the risk from moderate to low. An older house with a warm attic should expect closer to 10.3 days.
What to do about ice dams in Quincy
- Air-seal the attic floor: the gaps around the hatch, light fixtures, plumbing stacks and the top plates of interior walls. This is the fix that removes the cause, and it usually costs less than a season of contractor ice removal.
Which to spend on first: air sealing or heat cable.
Quincy winter, month by month
| Month | Snow (in) | Days on ground | Dam days |
|---|---|---|---|
| January | 5.8 | 10.3 | 3.2 |
| February | 4.1 | 6.3 | 1.7 |
| March | 2.1 | 2.1 | 0.3 |
| April | 0.7 | 0.2 | 0.0 |
| October | 0.1 | 0.0 | 0.0 |
| November | 1.0 | 0.6 | 0.1 |
| December | 4.0 | 5.5 | 1.4 |
Quincy next to nearby towns
Quincy ranks 198 of 225 Illinois cities here for ice-dam days, behind Arlington Heights at 21.5 days.
- Hannibal, MO 15 mi, 8.4 days
- Macomb, IL 52 mi, 10.6 days
- Mexico, MO 59 mi, 6.3 days
- Burlington, IA 62 mi, 10.0 days
- Jacksonville, IL 62 mi, 6.3 days
Where these numbers come from
NOAA 1991–2020 climate normals from Steffenville, 27.0 miles from Quincy. 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.
- The weather station is 27 miles away, far enough that local snow can differ.