Timing is most of the job. Sealer needs surface temperature, not air temperature, and it needs a dry window on both sides.
Updated 2026-07-16
Sealer cures by evaporation. Most manufacturers specify a surface temperature above roughly 10°C and rising, with no rain for 24 hours after application. In practice that puts the Ontario season somewhere between late spring and early autumn, and it means a warm afternoon in April can still be too cold if the ground hasn't come up.
Fresh asphalt needs to cure before its first seal — commonly cited as six to twelve months. Sealing too early traps the oils still leaving the surface and can leave you with a soft, marking driveway. If your driveway was paved this year, the right answer is usually next year.
Ask what surface temperature they're working to, what the rain window is, and what happens if the weather turns after they've started. A contractor who has an answer for the third question is the one you want.
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