Last reviewed October 31, 2026.
The roofer who came out in October says the old roof will make it through one more winter, probably. Now you have a choice: book the job before the cold sets in, wait for spring, or grab a January slot if one opens up.
The shingles, the weather records for Islip and the roofers’ own calendars each point to a slightly different answer.
What the shingle makers say about 40 degrees
Asphalt shingles stay put in wind because a strip of sealant glues each course to the one below. Owens Corning’s cold-weather bulletin (April 2026) says that strip is thermally activated, and that direct sun is what sets it off. Put shingles on in the cold and they may not seal until warmer temperatures arrive, and may take longer to lie flat.
Owens Corning starts its cold-weather steps when air and surface temperatures are at or below 40°F. At that point it recommends hand sealing every shingle along the roof perimeter, with four 1-inch dabs of asphalt roof cement on architectural shingles, and a gap of no more than 1/16 inch at the shingle ends so they do not buckle against each other in warmer weather.
Malarkey’s bulletin (October 2024) uses the same 40°F line, but says it is hard to name one ambient temperature that helps or hurts sealing, because the shingle’s own temperature depends on sun, wind, color, slope and direction. South and west slopes, it says, usually seal faster than north and east ones.
The Asphalt Roofing Manufacturers Association adds a handling warning (March 2022): shingles stiffen as the temperature falls and can crack if bundles are tossed around roughly in the cold.
How warm Islip gets, month by month
The National Weather Service office in Upton publishes daily 1991 to 2020 normals for Islip. Read against the 40°F line, they show how close a midwinter day comes to the shingle makers’ cold-weather threshold.
| Date | Normal high at Islip | Normal low at Islip |
|---|---|---|
| November 1 | 59°F | 42°F |
| November 30 | 49°F | 34°F |
| December 31 | 41°F | 27°F |
| All of January | 39°F to 41°F | 24°F to 27°F |
| March 1 | 44°F | 28°F |
| March 31 | 52°F | 36°F |
On a normal January afternoon at Islip, the air barely scrapes Owens Corning’s threshold. By the end of March the normal high has climbed back above 50°F. These are Islip figures, so other towns will not match them exactly.
When Long Island crews are busiest
Demand is the other half of the timing question. Cigna Roofing says late spring through fall is peak season and scheduling can be tight, and that late fall or early spring can sometimes give more flexible dates (March 2026). Bonac Builders in East Hampton calls summer the busiest season, with possible scheduling delays and higher prices, and says spring is easier to book than summer.
Rapid Restore NY calls fall often ideal but says demand is higher then, so it recommends booking early (October 2026). Long Island Exterior Co. says many homeowners benefit from winter scheduling because wait times are shorter.
We did not find a Long Island roofer who publishes a typical wait in weeks for any season.
Spring, summer and fall on the job
Home Team Construction in Mastic says spring and fall are ideal because roofing materials seal best in moderate temperatures, and that deep summer is fine but brutal on the crews. G&V Roofing in Merrick says late spring through early fall offers the most stable weather (April 2025).
Bonac Builders puts the best range for asphalt roofing at 40 to 85 degrees, and says metal and slate are more flexible year-round. Rapid Restore NY notes that spring storms can cause occasional delays.
Malarkey’s bulletin adds one summer tip: on hot days, crews should shingle in the morning and chase the shade for the rest of the day.
Winter jobs and hand sealing
Winter is not off the table on Long Island. Home Team Construction says winter installs happen routinely using cold-weather techniques, and that it works year-round. Long Island Exterior Co. says shingles need temperatures above 40°F for the adhesive to activate, and that it reschedules when conditions are unsafe or suboptimal.
If you book a winter date, ask the roofer how it will meet the manufacturer’s cold-weather instructions for the exact shingle on the quote.
That matters for the warranty. Malarkey says its wind warranties apply only once shingles are sealed, by hand or by the strip, and that failure to seal in adverse conditions is not a manufacturing defect. It also says shingles that are not lying flat after a cold install may need anywhere from a couple of weeks to several months of warm sun to relax.
When waiting is the wrong call
All of this assumes the roof can wait. Water coming through a ceiling is a repair call today, whatever the season, so start with emergency roof repair.
If winter is your worry because of ice along the eaves, our ice dam guide covers that problem separately. Once a date is set, see how long a roof replacement takes and how to get the house ready for the tear-off.
