When to Paint the Outside of Your House in the Lower Mainland

The exterior painting season in the Lower Mainland runs from roughly April to early October. It is set by two things: most exterior acrylic paints specify a minimum application temperature around 10°C, and the film has to stay dry long enough to cure — which is considerably longer than it takes to stop feeling wet to the touch. A soaked wall also needs days to dry before it can be painted at all.

Why the window is narrower than the calendar suggests

People tend to look at a forecast, see a dry day, and assume that is enough. Three separate conditions have to line up, and a single dry afternoon only satisfies one of them.

The paint needs the surface and the air above its minimum application temperature, not just at noon but through the overnight low, because a film that gets chilled before it has cured does not coalesce properly. Manufacturers commonly specify 10°C, and some low-temperature formulations are rated lower — the tin will tell you, and it is worth reading rather than assuming.

The film then needs uninterrupted dry time. Recoat times on the label are minimums under ideal conditions; the full cure that gives the coating its durability and washability takes much longer. Rain on a partly cured film is what produces surfactant leaching — those streaky, glossy runs that appear down a freshly painted wall.

And the substrate has to be dry to begin with. This is the one that catches people out here. Cladding that has been rained on holds moisture well after it looks dry, and painting over it traps that moisture behind the film, which is a direct route to blistering and peeling.

What the climate data actually says

Environment and Climate Change Canada's climate normals put Vancouver International Airport at roughly 1,190 mm of precipitation a year, spread over something like 160 days with measurable precipitation. That is the drier end of the region: stations sitting higher and closer to the Coast Mountains — which is where Coquitlam, Port Moody and the hillside neighbourhoods sit — record noticeably more.

Put differently, close to half the days in a Lower Mainland year have some precipitation, and the great majority of the dry stretch falls between late spring and early autumn. That is the window, and it is not a long one.

Why exposure matters more than square footage

Two houses of the same size on the same street can need different work, because paint does not fail evenly.

South and west elevations take the ultraviolet load. They fade, they chalk, and the film gets brittle. That is a sun problem and it looks like a colour problem.

North and east elevations barely dry in winter, especially under overhanging conifers. What fails there is biological: mildew growing in the film, which shows up as dark blotching. Painting over live mildew feeds it — it comes back through the new coat, sometimes within a season. It has to be washed and killed first, and the topcoat is worth choosing for mildew resistance rather than only for colour.

This is why a proper quote walks all four sides of the house rather than measuring the front. On a shaded, inlet-facing house in Port Moody the north wall may be the whole job; on an exposed south-facing house in Burnaby it may barely need attention.

Book in the winter, paint in the spring

The counterintuitive part: the best time to arrange exterior painting is months before anyone can do it.

Everyone in the region is trying to book into the same five or six months. Quotes requested in February and March get the early-season slots, which are the ones with the most schedule slack — so if a week gets rained out, there is somewhere to move you to. Quotes requested in July are competing for what is left of a season that is already half spent, and a wet September can push the job to next year.

Winter is also the right time to do the inside of the house. Interior work has no weather constraint at all, so a sensible plan for a house that needs both is interior work through the wet months and exterior work in the dry ones.

What to ask any exterior quote to spell out

Ask how the surface will be prepared, specifically: washed how, scraped back to what, which bare areas get spot-primed. Ask whether failing caulk is being replaced or painted over. Ask whether rotted fascia and trim are being cut out and rebuilt or filled — filler in a rotted board is a decoration, not a repair. Ask how many coats, and of what.

A quote that answers those in writing can be compared to another quote that answers them. A single number cannot.

We give free on-site quotes across Coquitlam, Port Coquitlam, Port Moody, Burnaby and New Westminster, and we would rather tell you in November that your house should wait until April than take the deposit and paint a damp wall.