Sunlight prevents the paint from drying smoothly. Certain types of paints dry quicker than others, especially latex. When you're painting in hot, sunny weather, more time is needed between coats. When a second coat is added too soon, the paint may peel off from the moisture collecting underneath.
Paint, like most colored materials, slowly decays under the presence of UV light. This happens so gradually that it is probably not something you will notice until your paint is significantly faded. However, extremely dark and light colors do tend to fade much faster than other colors.
High temperatures bake paints. At best, a too-high temp will cause the paint to dry too fast. With too hot of a surface, the paint never gets a chance to adhere and possibly leaving you with a cracked, peeled, or blistered exterior (below).
Although picking a sunny day for painting may seem like the best idea, too much direct sunlight can actually cause paint to dry far too quickly. To stick properly to the material, the paint needs a little time to soak into the surface before it's fully absorbed.
As you apply paint to a surface, the water naturally evaporates resulting in the formation of a paint film on your surface. Painting in hot weather will cause water to evaporate at a much quicker rate, leading to rapid drying times and incomplete film formation.
Sunlight prevents the paint from drying smoothly. Certain types of paints dry quicker than others, especially latex. When you're painting in hot, sunny weather, more time is needed between coats. When a second coat is added too soon, the paint may peel off from the moisture collecting underneath.
Don't paint on hot days, in the rain or during windy weather. Ideal temperatures for painting are between 50 and 90 degrees Fahrenheit. Hot weather causes the paint to dry too quickly, as does direct sun. When possible, wait for the shade.
Oil-based paint - dry to the touch in 6–8 hours and ready to recoat in 24 hours. Latex paint - dry to the touch in about 1 hour, and you can safely recoat in 4 hours.
A common painting misunderstanding is that it's advised for all inside paint jobs to be done during the winter. In contrast to this general belief, any time of the year is actually very suitable for interior projects – especially summer time.
Painting in the Heat
Latex paints are usually the best for all exterior projects. Painting when it's too hot can cause bubbles and blisters to form in the paint. Consequently, we recommend not painting in temperatures above 90 degrees Fahrenheit.
The ideal temperature range for painting your home is between 15°C and 30°C, to allow for the best results. Sometimes though, we don't get ideal painting conditions. But, yes, it can be too cold to paint even if it's dry. Much like water, water-based paints have a freezing temperature of 0°C.
As a rule of thumb, the best temperature to paint outside is 40 to 90 degrees Fahrenheit, with an ideal painting temperature range of 50 to 70 degrees Fahrenheit. This translates to roughly 4 to 32 degrees Celsius as the best temperature range and 10 to 21 degrees Celsius as ideal temperatures to paint exteriors.
Painting in Low Light
Avoid painting interior surfaces in dim light. The painted surface may look fine at first, but when you uncover the windows or turn on bright lights you'll likely see thin patches and other imperfections. Always make sure to have lots of bright light when painting.
The ultraviolet light that the sun emits degrades paint. This process is called photodegradation. The first phase in this process is photolysis, where the polymer (resin) absorbs ultraviolet radiation. As it does, it becomes excited and is raised to a higher energy state than normal.
Extreme dry heat could cause more evaporation of critical chemicals in the paint, including water, altering consistency and color. The alternative: store paint in temperature-controlled utility rooms; some people even store small cans on shelves in large pantries.
Sunlight contains powerful UV rays that react with the pigments in the paint, slowly bleaching them out. This is most visible in dark or brightly colored paints, as the color will lose intensity slowly.
If your storage room has experienced freezing temperature or extreme heat, your paint may be ruined. Extreme temperatures to paint are below 50°F or above room temperature, or 72°F. When exposed to extreme temperatures the paint components may separate, which makes them unusable.
Humidity wrecks the drying process of paint by introducing extra water into the equation. Usually, some humidity is acceptable. A little water won't be a problem so long as it evaporates faster than the solvent in the paint. At best, you'll have longer drying times.
When your surface is wet, the moisture in it prevents paint from completely adhering to your surface. And this is a recipe for a painting disaster. When air and water seep in, it may create cracks and peels. See, when you're painting in the rainy season, it's not the rain that you should be looking out for.
1. Avoid the Sun. The sun is your biggest enemy in the summer because it can super heat surfaces 20°F or more above air temps depending on the color of the surface and the exposure. Direct sunlight on freshly applied paint will often cause a lack of adhesion and the dreaded bubbles to form in the finish.
Does paint dry quicker in heat or cold? Paint dries quicker in heat. However, high humidity doesn't allow paint to evaporate adequately. Dry heat, as opposed to humid heat, is best.
Paint will take forever to dry in a room that's too cold (think 50 degrees Fahrenheit or cooler). Meanwhile, if the room is too hot (70 degrees Fahrenheit or warmer), you'll end up with a top layer that dries too quickly, leaving the bottom layers wet and leading to an imprecise paint job.
Take frequent fresh air breaks while painting. Avoid freshly painted rooms for 2 to 3 days, whenever possible. Keep young children and individuals with breathing problems from freshly painted rooms. Leave painted areas if you experience eye watering, headaches, dizziness, or breathing problems.
For optimal results, the painting should be completed when relative humidity is between 40-50%. While too much humidity is damaging to paint, you still want some to reach a well-calibrated drying time. Avoid painting when the humidity is 85% or more.
When planning out the best time to paint your home's exterior, you should be conscious of upcoming rainy days. For best results, you should have 5 consecutive, dry, sunny days to allow your paint to fully dry. You need 6 to 24 hours, depending on your paint.