There is a considerable amount of conflicting information on whether or not it is a good idea to paint a home when it is raining. Most everyone knows that you shouldn't paint a surface that is being actively rained on, but can you paint an exterior surface while it is raining if the surfaces are sheltered from direct rainfall? and do the humid conditions of a rainy day affect indoor painting?
Among the questions often asked:
- Will the paint to run if you apply it on a rainy day?
- Will the paint take so long to dry that it will affect its eventual cured state?
- Will painting in the rain affect the paint's color or texture?
The Short Answer
Yes, you can paint both the exterior and interior of your house when it rains, though there are limitations when it comes to painting exteriors.
There are no reasonable limitations when it comes to painting interior surfaces when it is raining outside. As long as the interior walls are dry and you do not expect them to get wet, you can paint. Just keep in mind that windows left open during interior painting often experience sprinkles on the sill or the wall below the window. And you can expect it to take longer for interior paint to dry in the humid conditions of a rainy day than it does on dry, sunny days. This may delay the time until you can apply a second coat of paint where it is necessary.
Limitations on Painting Exteriors
Many experts recommend against applying paint at first sight of a rain cloud. But if you live in a rain-prone area, you might never get any work done if you retreated inside the moment the first drop fell. Professional painters cannot afford to stop exterior painting every time a rain cloud comes onto the horizon. So how do they do it?
Painting season is not determined by terms such as "fall" or "winter," but by climatic conditions such as moisture and temperature. As long as you are safely within those climactic boundaries, it can be considered painting season. When professional painters assess whether conditions are right for painting exteriors, there are several questions they ask:
Is the surface visibly wet right now? Even a few drops count as wet. An actively wet surface can't be painted until it dries completely.
If not, when was it last wet? Even if a surface does not appear to be wet, it might have latent moisture that could affect your paint. An exterior wall that was rained on may require 4 hours of drying time in direct sunlight and temperatures at or above 72 degrees Fahrenheit to be fully dry for painting. Ideally, you would want to wait a full day for the surface to dry. Even if the flat surfaces have dried, other areas might not be, such as:
- Sections that are hidden from the sun
- Trim and molding
- Hairline cracks in the siding
- Nail holes
A common scenario: You touch the wall and it feels dry. But when you run your brush across a nail hole, it releases built-up water. If you do not catch this right away, the water drips down your newly painted surface, creating light streaks. The only cure for this is an additional coat of paint.
Is the temperature right? Is the outside temperature below the minimum recommendation as specified on the paint can? Temperature and moisture work in conjunction with each other. The lower the temperature, the longer it will take for your exterior surface to dry.
Will temperatures drop below minimums? You shouldn't paint if the prediction is for temperatures to drop below the minimum within 8 to 10 hours of paint application. Check the paint can label for the temperature recommendations.
Be reasonable, though. Some paints can be applied in temperatures as low as 34 degrees Fahrenheit, but if you are painting at exactly 34 degrees at 10:00 am, and you expect it to hit freezing at 6:00 pm, you are unreasonably pushing the envelope. Give yourself a buffer zone.