With the advent of newer paints, one of the major changes that has come about in some of the exterior products is the paint’s ability to withstand colder elements while curing. This allows exterior painting coverage to properly cure and adhere in temperatures below what used to be acceptable outdoor norms, considered to be 50 degrees or so. Not all, but many new products can now set and cure properly at temperatures as low as 38 degrees. It is generally agreed that oil paints can be applied in lower temperatures than latex finishes. Technology is great but we still believe that temperatures should be above 45 degrees as a low temp overnight at least.
On the other side of the coin, temperatures should not be exceeding 90 degrees for painting, even lower for latex products. Paint will not bind properly at higher temperatures which can lead to peeling and cracking issues before reasonable life expectancy, and in particular with latex paints as it will tend to dry too quickly, practically as you paint. You will notice Pro Painters work their way around the house or building in front or behind the sun's direct light and exposure on the area being painted. Surfaces exposed to the sun’s rays become extremely hot, too hot to paint. Another temperature issue is extreme fluctuation during a given day. Spring and fall tend to be the best times to start an exterior house painting job because daytime temps and evening temps do not vary greatly, a quick look at the forecast will help decide acceptable, stable conditions. Overall, best conditions for exterior painting is between late April and mid-October for northern climates and between mid-March and mid-December for more southerly locations.
What If Moisture Is Present During Exterior Painting?
It is never time to paint if excessive humidity is present. Humidity can form at a couple of different times, the first kind is that early morning dew, or frost which usually appears after a cool evening and any painting must be delayed until that moisture has ‘lifted’ and surfaces are dry to the touch. The second way moisture can create problems for painting is while humidity exists in the air on hot days and measured levels exceed 70%. Even if surfaces feel dry on a humid day, make no mistake, the surfaces can be wet inside as many surfaces are porous and tend to hold water. Of course, no one paint in the rain but using rain to measure the likelihood of humidity is fairly reliable. If rain has just stopped, or it is on its way on a hot hazy day, it’s pretty safe to conclude that there may be too much humidity for the best results when performing exterior painting.