The season
When is sealcoating season in Wisconsin?
Sealcoating season in Wisconsin runs from about May through early October, and it is the overnight low rather than the daytime high that opens and closes it.
The numbers
- Roughly May through early October in northwestern Wisconsin.
- Asphalt emulsion sealer wants 50 degrees and rising, and it wants the night to stay there too.
- Sealer needs a dry window after it goes down, normally 24 hours.
- Crack filling has a wider window than sealing does, and it runs into the fall.
Why the night decides it
Sealer is water based. It cures by the water leaving, and that stops happening when the pavement gets cold. A 68 degree afternoon in April with a 38 degree night is a bad sealing day, because the coat goes on fine and then sits wet through the night and cures soft or not at all.
That is why a contractor watching the forecast in northwestern Wisconsin is watching the lows. Two warm days on either side of a cold night is not a window.
Why spring starts later than it feels like it should
The ground here holds frost after the air has warmed up. A lot can be dry on top and still be moving underneath, and a surface that is still settling is not one worth coating. Repairs done before the frost is out get undone by the ground coming back up.
So the first real work of the year is usually assessment and crack filling, and the sealing follows once the nights hold.
The other end of it
The fall end is the same rule running backward. Early October afternoons are still warm and the nights are not, and a late coat that never cured properly wears off over the first winter.
There is real work in October and November, and it is the repair, the crack filling and getting a lot ready for the plow. The sealing waits for spring.
Where these numbers come from
- Application temperature and cure windows are the asphalt emulsion sealer manufacturer's own label conditions.