How long exterior paint lasts depends not only on the paint but also on the weather it's applied in. With Toronto's cold winters and changeable spring weather, choosing the right time makes a real difference.

Why temperature matters

As water-based (latex) paint dries, its binder particles need to fuse into a film. If the air or surface is too cold, the film doesn't form properly, leading to poor adhesion, cracking and early peeling.

• For most standard exterior latex paints, the minimum is about 10°C (50°F).
• Some newer paints can be applied down to about 2°C (35°F) according to their manufacturers, but temperatures still need to stay above that minimum for 24–48 hours after application.
• What matters is not just the air but the surface temperature of the wall. Walls coming out of winter can stay cold for a while after the air warms up.

Humidity and dew

There should be no dew or rain on the surface while the paint dries. Dew on fresh paint can leave blotchy, shiny streaks. Start after the morning dew has lifted and finish a few hours before evening dew sets in.

The best window for Toronto

The period from late spring, once night-time temperatures are reliably warmer, to early fall, before it cools down, is generally the best window. In mid-summer, walls in direct midday sun can get very hot, so paint those sides while they are in shade.

Quick checklist

• Check the minimum application temperature on the paint can.
• Look at the 48-hour forecast; no frost or rain expected.
• Clean the surface, repair cracks and prime if needed.
• Schedule sunny sides for the cooler part of the day.

Planning to paint your home's exterior? Contact us for a free estimate before the season fills up.