Can a Roof Be Repaired in Winter? What Works in the Cold

Federal climate normals for Grand Rapids (1991 to 2020, measured at the airport) put the average daily high at about 36°F in December, 31°F in January and 34°F in February. November averages about 47°F and March about 45°F. In other words, the three core winter months run below the temperature that many roofing products name as their floor, and the shoulder months hover right around it.

Air temperature is only part of it. A north-facing slope in shade can stay colder than the air all day, while a south slope in full sun can warm well above it by early afternoon. Frost and dew on the surface matter as much as the thermometer, because almost every adhesive and cement used on a roof requires a clean, dry substrate. That is why a good winter repair is planned around the slope, the sun and the time of day, not just the forecast high.

Every product on a roof has its own instructions, and the numbers below come from those documents. They show why one repair can be done at 25°F and another cannot. Your roofer should follow the instructions for the specific products on your roof, which may differ from these examples.

Some repairs depend on a bond that simply will not form reliably on a frozen, frosty roof. That does not mean they cannot be touched until April. It means the honest approach is often two steps: stop the water now with something rated to hold through the cold, then return on a dry day in the 40s, which West Michigan does get in most winters, to finish the work to the product's instructions.

Flat and low-slope membrane seams are the clearest example, because they rely on adhesives, primers and tapes with temperature floors. Large sections of new ice barrier at the eaves are another, as is any repair where the deck underneath has to be dried out before it is covered. If you are told a winter repair is permanent, it is fair to ask which products were used and whether their instructions allow the temperature that day.

Monthly normals tell you how cold an average day is. For planning a repair, the more useful question is how many days in a month actually reach the temperatures printed on roofing products. We counted them in NOAA's daily records for the Grand Rapids airport station over the same 1991 to 2020 period the normals use. The figures are 30-year averages, so any single winter can run well above or below them.

In December the high reached 45°F on about 6 days and 40°F on about 10. January averaged under 3 days at 45°F or warmer and about 5 or 6 days at 40°F. February averaged under 4 days at 45°F and about 7 at 40°F. At the other end, the high never got above freezing on about 17 days in a typical January, about 12 or 13 in February and about 10 in December. The shoulder months open up quickly: November averaged 17 days at 45°F or warmer and March about 13 or 14, and by April it was about 26.

Snow cuts into those days too. Over the same 30 years the station averaged about 60 inches of snow from December through February, with roughly 19 days in those three months bringing an inch or more. A warm afternoon right after a snowfall is not a workable day until the roof is cleared and dry, and freeze-thaw swings are most frequent in March, when the temperature crossed freezing on about 17 days a month on average.

What this means in practice: a repair that needs 45°F and a dry surface may wait one to three weeks for its window in midwinter, and sometimes longer in a cold January. That is why the temporary-then-permanent approach above is normal in West Michigan rather than a sign of a careless roofer. It is also why the warm days that do come in winter get booked first for adhesive-dependent work.

Small problems found in the fall are easier and cheaper to fix in the fall. A cracked pipe boot, lifted shingles or loose flashing noticed in October can be repaired with every product inside its temperature range and every sealant strip given a few warm afternoons to bond. The same problem found in a January leak means working around snow, cold-rated materials and a shorter day.

At Stellar, repairs run year round. Standard repairs are scheduled every week for the following week and nearly all are completed within two to three weeks, winter included. For an active leak, the phone is watched around the clock, and for a true emergency we are usually on site within 24 hours, weather permitting and if the roof is safe to access, prepared to stop the water the same day.