The short answer
In most of the US, Canada and southern Australia, late spring to early summer and early fall are the best times: mild days, cool but not cold nights, and lower humidity. In hot climates, the cooler months are often better. What counts is not the calendar but the conditions on the days you paint and the nights after.
Temperature
| Paint type | Typical minimum temperature |
|---|---|
| Standard exterior latex (acrylic) | Often about 50°F (10°C) |
| Low-temperature latex formulas | Some are labeled for 35°F (2°C) |
| Oil-based (alkyd) | Often about 40 to 50°F (4–10°C) |
These are typical label figures; the can you buy has the real limits. The minimum applies to the air and the surface, and it needs to hold through the night while the paint forms its film. A 60°F afternoon followed by a frost is not a good painting day. Very hot surfaces cause problems too: paint dries before it levels, leaving lap marks and poor adhesion.
Season by region
| Climate | Usually the best windows | Watch for |
|---|---|---|
| Northern US and most of Canada | Late spring to early fall | Cold nights in spring and fall, short seasons |
| Southern US | Spring and fall | Summer heat, humidity and afternoon storms |
| Southern Australia | Spring and autumn | Hot, dry summer days and winter rain |
| Tropical northern Australia | The dry season | Wet-season humidity and rain |
Moisture: dew, rain and humidity
- Dew. Wait in the morning until dew has dried off the walls. Stop early enough in the afternoon that the paint is dry to the touch before evening dew forms. Fresh latex paint hit by dew can develop sticky, streaky surfactant stains.
- Rain. Most labels give a rain-free period after painting. Plan for a dry forecast for the day and night.
- Wet siding. After rain or washing, let the wood or stucco dry before painting. Wood often needs a day or more of good drying weather.
- Humidity. High humidity slows drying, which stretches the time paint is vulnerable to dew and rain.
- Dew point. A common guideline for coatings is to keep the surface at least 5°F (3°C) above the dew point so moisture does not condense on it.
Painting late in the season
Fall painting can work well: humidity is often lower and the sun is less harsh. The risk is shorter days and colder nights. Paint earlier in the day so the film has time to form before temperatures drop and dew arrives, and check the overnight low, not just the daytime high. If cold weather is coming, it is often better to finish one side properly and leave the rest for spring.
Sun and shade: follow the shadow
Avoid painting a wall while direct sun is beating on it. A classic plan is to start on the west side in the morning, while it is shaded, and work around so you paint the east side in the afternoon. Dark colors absorb heat and are the most sensitive to this.
Wind
Strong wind dries paint too fast and blows dust and debris into the wet film. It also makes ladder work dangerous. Pick calm days, especially for spraying.
A practical weather checklist
| Check | Aim for |
|---|---|
| Forecast low tonight | Above the label minimum |
| Surface | Dry, not hot to the touch, out of direct sun |
| Rain | None during the label's rain-free period |
| Dew | Start after it dries; finish hours before evening |
| Wind | Light |
Worked example: plan the paint, then the days
A two-story house 36 × 28 ft has a 128 ft perimeter and 18 ft walls. With two 28 ft gables 7 ft tall, two doors and sixteen windows, it has about 2,220 sq ft of siding to paint. Two coats at 350 sq ft per gallon need about 12.7 gallons, so buy 13, or three 5 gallon buckets. If the siding is rough-sawn wood, plan on about 15.9 gallons. Upper walls mean ladder or scaffold work, which is slower, so plan fewer square feet per day than on a single-story house. Get your own number from the exterior paint calculator, and buy it all at once so the color matches.
Two coats mean at least two good painting windows on each wall, separated by the recoat time on the label. Prep, washing and drying time come first. Watch a week of forecasts and leave slack for a rain day.
Prep matters more than timing
- Wash the siding and let it dry. Scrape loose paint, sand edges smooth and prime bare wood.
- Caulk gaps around trim and windows with exterior sealant before painting.
- In the US, homes built before 1978 may have lead paint. Test before scraping or sanding, and use lead-safe practices.
- Set ladders on firm, level ground, keep three points of contact and stay well away from power lines.
Frequently asked questions
What temperature is too cold to paint outside?
Many standard latex paints need at least about 50°F (10°C) in the air and on the surface, including overnight. Some low-temperature formulas go down to 35°F. Check the can.
How long after rain can I paint my house?
Wait until the surface is completely dry. Wood siding often needs a day or more of dry weather after heavy rain.
What time of day is best to paint outside?
Start after the morning dew has dried, avoid walls in direct sun, and stop early enough that the paint is dry before evening dew.
Do the math for your own project.
Open the exterior paint calculator