When planning any outdoor or indoor painting project, temperature matters. Humidity, other weather conditions and surface temperature also factor into the equation.

Southwest home with white exterior and clay roofing.

Optimal Temperature to Paint: 1.7 ºC to 37.8 ºC

Temperatures will often dictate how easy a painting job will be to execute and how well it will turn out. The optimal painting temperature would be 25 ºC (77 ºF), but it is still acceptable to paint within a wide range of temperatures. Since temperature varies more widely outside, that is where most issues arise. We recommend planning your painting project for temperatures ranging from 1.7 ºC to 37.8 ºC (35 ºF to 100 ºF) and when humidity is as low as possible. Every Benjamin Moore product has its own specifications and optimal temperature range, which you can find on the product label or its Technical Data Sheet.

Paint Temperature, Surface Temperature, Humidity and Rain

In most cases, paint will be the same temperature as its environment, so consider where it is stored. A paint can left in an unheated garage all winter will retain a cold temperature for some time. Bring it inside overnight so the paint can warm up to a temperature within its specified acceptable range.

It’s always best to avoid painting or staining in direct sunlight. The surface you’re painting has its own temperature, which may differ from the ambient, or air temperature. A black wall that has been in direct sunlight for a few hours is likely to be substantially hotter than the air. If you have any questions about surface temperature, measure it with an infrared thermometer. The surface should not be hotter than the specified acceptable range of the paint you’re using.

If the humidity is too high, paint can dry improperly. The industry standard is to paint on a surface whose temperature is more than 5 degrees above the dew point—the temperature at which water droplets begin to condense.

Clearly, you want to avoid rainy conditions when taking on an exterior painting project. If you’re surprised by rainfall during your project, stop painting immediately; wait until the rain stops and your painting surface is dry. 
Your painting project is bound for success when you avoid rain, excessive humidity and extreme temperatures. Have more questions? Your local Benjamin Moore retailer is always happy to help. Need help choosing a wood stain colour and opacity? Explore this step-by-step guide.