The question this page answers
When can the outside of a house in Altoona be painted, and when does it make more sense to wait? Paint labels answer half of that with their temperature limits. NOAA's normals answer the other half by showing how often the weather meets them. Below are the figures and what a painter does with them.
The station behind the temperatures
The temperature figures on this page come from NOAA's 1991–2020 climate normals for the ALTOONA 3 W station. NOAA computed them from 27 years of record within 1991–2020. They describe that station, not your yard.
The ends of the year
At ALTOONA 3 W, January's normal high is 33.8 degrees and its normal low 18.8 degrees. A normal year carries an average of 128.1 days with a low at or below freezing and 38.9 days whose high never rises above freezing.
Most exterior paints list a minimum application temperature above a January normal high like that. In practice, the coldest months are for planning, ordering and indoor work, not for siding.
The middle of the year
July's normal high at the same station is 81.4 and its normal low 61.3. A normal year has only 5.7 days reaching 90 degrees or above. For a painter, that combination is useful: July's normals sit inside the temperature range most exterior labels allow, and very hot days, which cause their own problems with fast drying and lap marks, are few.
The months between the two ends are where judgment comes in. A spring or fall day can reach a comfortable afternoon high after a night near freezing, and the surface may still be cold or damp from dew when the crew wants to start. Ask how the painter handles those shoulder days.
Humidity on summer days
For moisture, NOAA's engineering weather data uses a separate station. In an average year at Altoona/Blair, NOAA counts about 97 hours with the wet-bulb temperature above 73°F and about 826 hours above 67°F. Those hours slow the drying of water-based paint and stretch the time before a second coat. On a damp afternoon, a crew may finish one side and wait for the next day to recoat rather than trap moisture between coats.
Fitting a job into the window
With the cold months ruled out for exterior coating, the work has to fit into the warmer part of the year. That affects a few practical things:
- Booking. The warm months are when most homeowners want exterior work, so walk-throughs and start dates fill early.
- Repairs first. Rotten trim, failed glazing and loose siding should be fixed before the painting window opens, or at least before the crew arrives, so prep doesn't eat the good weather.
- Splitting the job. A large house can be painted in phases, with the most weathered walls first.
- Late starts. A job started late in the season may not finish before nights get cold again. Ask what happens then.
Our exterior painting page explains the prep and coating order in full.
Pennsylvania registration
The Pennsylvania Office of Attorney General says painting is on the list of home improvements under the Home Improvement Consumer Protection Act. The card below quotes the registration rule.
Things to settle on the estimate visit
- What are the lowest air and surface temperatures your products allow?
- On a cool morning, which side of the house do you start on?
- How long does each coat need before a second coat, and what if it's humid?
- If the season closes before you're done, what's the plan?