gardens3 min read

The best weather conditions for painting outside

House exterior

WordsMaha Elley

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Planning to paint a surface outside of your home? Before you kick off, take a look at the weather forecast. When you paint your exterior surfaces can have just as much of an impact on the finished product as the steps you follow.

Here are a few tips to help you pick the best weather for your outdoor paint project: 

  • Check the next day's weather forecast before starting a large exterior or masonry paint project. 

  • Choose a nice, dry day for painting to allow the paint to set and dry thoroughly. 

  • A poor exterior paint job is usually the result of one of two things: bad weather on the day or lack of surface prep. Get those things right (coupled with the right exterior paint) and you’re looking at a paint job that could last you up to 10 years. 

  • Your exact drying times will depend on the temperature and the relative humidity during paint application. Let the paint dry for at least 16 hours/overnight without any exposure to rain or frost. Keep drying time to a minimum by choosing a dry day.

In a nutshell: choose the right weather for painting and you’re well on your way to a flawless finish. Learn more about the best weather conditions for painting outside below.

The effects of direct sunlight on painting outside 

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.

Choose a day that’s dry and not too sunny and you’re all set. Or just paint a bit later in the day when the sun is going down.

The effects of rain on painting outside 

This is a more obvious one, but it has to be said: avoid painting any exterior surface when it’s raining outside, even if it’s just a light drizzle. The rain will wash away the paint before it’s fully set, leaving you with a less than professional finish.

The effects of wind on painting outside 

While a bit of a breeze is not an issue, painting externally in very windy conditions can lead to the binding agent – solvents or water –  evaporating too quickly. You also run the risk of sediment being blown into the wet coating.

The effects of high temperatures on painting outside 

Although you’d ideally paint outside on a day where the temperature is above 10 degrees, overly high temperatures can come with high humidity levels. 

When humidity levels are high, there’s more moisture in the air, which means it can take longer for the water or solvents within the paint to evaporate. This can affect the drying time, so we’d recommend skipping an overly hot day.

The effects of low temperatures on painting outside 

If you’re using paint that’s based in natural oils and resins, it can become more viscous at low temperatures. This means that when painting in cold weather, some paints will become very thick or semi-solid. Not ideal.

The ideal weather conditions for painting outside 

So, you may be wondering, when exactly can I paint outside for the best finish? We’d recommend an ideal example of a weather condition of 18 degrees with 65% relative humidity.

For the best results, paint above 10 degrees, apply a second coat after four hours, then allow to dry overnight before potential exposure to frost or rain.

In summary:

  • The ideal air temperature for painting outside is 18 degrees (or at the very least, above 10 degrees)

  • Relative humidity of 65%

  • Warm, dry, cloudy conditions

  • No risk of rain during the application or drying process. And you’re all set!

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