For paint to dry properly, temperatures need to be above 45 or 50 degrees Fahrenheit, depending on the type of paint. Solvent-based paints require temperatures to be 45 F or higher, whereas latex paints require 50 F temperatures or higher. Refer to the manufacturer's instructions for paint-specific instructions.
The concern for solvent-based paints in low temperatures is thickening, which causes the paint to apply heavier and the paint brush to thicken. This causes slower dry times, causing the paint to run, sag or wrinkle. Thicker paint also leads to less coverage from each gallon of paint, reducing its overall coverage. Solvent-based paints also dry through oxidation, so the amount of sunlight available during the day is also an important consideration.
Below 50 F, latex paints dry at a much slower rate, which can cause the paint to fail prematurely as it does not adhere properly to the surface. The issue is compounded when humidity is high. When painting on humid days, ensure the temperature is above 50 F and that the project is finished at least 2 hours before sunset to allow for proper drying time. Some manufacturers offer latex paints that are able to dry in temperatures as low as 36 F, which is ideal for colder climates or painting during colder months. When choosing paint for a project, consider the current temperatures and read the manufacturer's instructions to determine the right paint for the job.