Two stations, two kinds of figure
NOAA's U.S. Climate Normals for the Boulder, CO station average 138.2 days a year with a low at or below 32°F and 92.8 inches of snowfall a year. For moisture, the figures come from a different station: in an average year at Denver/Stapleton, about 25 miles from Boulder, NOAA counts about 0 hours with the wet-bulb temperature above 73°F and about 6 hours above 67°F.
The first figure is the one that shapes a painting calendar. A low at or below freezing on that many days means the overnight temperature, not the afternoon one, often decides whether an exterior coat can go on.
How cold limits outdoor paint
Every exterior paint and stain carries a minimum application temperature on its label, and most say the air and surface must stay above it for some hours afterwards while the film forms. Some products are formulated to go on in cooler conditions than others. Either way:
- A coat applied in the afternoon can be spoiled by a freeze that night.
- Cold slows drying, so dew or frost can settle on a film that is still soft.
- Surfaces in shade stay cold long after the air warms.
- Wood that has held snow or meltwater needs time to dry out before it will take paint.
A painter planning exterior work in the shoulder seasons will check the overnight low for the days after each coat, not just the day it goes on.
Snow, meltwater and the bottom of the wall
Snow piled against a house, or meltwater dripping from the roof edge, keeps the lowest courses of siding and the bottoms of door frames wet for long periods. That's often where paint fails first. Before painting, look closely at:
- the bottom row of siding and the trim board along the foundation;
- the lower ends of door and garage door frames;
- sills and the undersides of window trim;
- deck boards and stair treads close to the house.
Soft or swollen wood there needs repair before paint, and end grain needs sealing. Our exterior painting page explains wood repair and priming, and the deck and fence staining page covers horizontal wood.
The case for doing the inside in winter
When outdoor painting isn't practical, interior work carries on. Winter is a good time for:
- ceilings and stairwells, which need the furniture moved anyway;
- kitchen cabinets, if a heated space is available for doors to dry;
- trim and doors throughout the house;
- full-room color changes.
With the house closed up and heat running, rooms still need some airflow so paint can dry and odors can clear. Our interior painting page and cabinet page explain those jobs.
Lead and older homes
Under EPA's Renovation, Repair and Painting Rule, anyone paid to do work that disturbs paint in homes, childcare facilities and preschools built before 1978 must hold RRP certification, firms included, even sole proprietorships, and their workers must be trained in lead-safe work practices. If the house predates 1978, you can ask whether the firm holds RRP certification; keep that as the only credential ask. Then ask how dust and chips will be kept out of the rest of the house and out of the yard.
Planning the year
- Get exterior quotes well before the weeks you want the work done.
- Agree in writing what happens if cold stops the job partway.
- Fit interior rooms into the colder months.
- Leave fresh exterior paint time to cure before snow is likely to sit against it.
Our pricing guide explains why timing and access can change a price.