How Long Does Exterior Latex Paint Need to Dry Before Rain?

woman painting house exterior siding
  • 1-200 hours
  • Intermediate
  • 0-3,000

The short answer is that latex paint is typically dry to the touch in about an hour. However, you should wrap up any exterior painting projects four to six hours before the rain rolls in.

Whether the project is a small one in the garden or the entire exterior of the house, painting outside leaves you, and your paint, exposed to the elements. Depending on the time of year and the climate, you may be battling impending rain as part of your project challenges. Obviously you can’t paint while it’s raining, unless you’re eager to try out abstract painting on the side of your home or fence. But the amount of time your paint project is still in danger of being ravaged by the effects of rain after you complete painting depends on several factors.

1. Temperatures

When you read the directions on a paint can, you’ll find recommendations for the ideal temperature range in which to paint. When it’s too hot, paint may have a difficult time adhering to the surface because it dries too quickly. It can also result in bubbling and flaking paint, which is a big mess to repair.

On the other end of the spectrum, cool temperatures result in paint taking a long time to dry. The perfect range for most paints is between 50-85 degrees Fahrenheit, but read your product label for accuracy and avoid painting when the temperature is outside this range.

To estimate whether your paint will dry before the rain rolls in, expect paint to be fine within an hour if temperatures are near the top of the range. If at the lower end, use caution unless the rain isn’t expected to hit for another four hours or more.

bright yellow home siding with painted wood, window, and small shrubs

2. Humidity

While temperature is a significant factor in how your paint will perform, humidity is an even bigger piece of the puzzle. Humidity refers to the amount of moisture in the air.

When humidity levels are high, the water content in the paint doesn’t transfer, or escape, to the air as easily. Therefore, any type of paint will take longer to dry in high humidity. The humidity may also affect the finished look of the paint job with dripping or streaking that will require sanding before reapplying more paint.

Although you may be in a hurry to squeeze the painting task in before the weather hits, it may cost you more time in the long run if humidity ruins your coat. Don’t plan to paint if humidity measures above 50% and if you see fog on the horizon, you can bet humidity is in the air.

purple metal roof with bright paint job under falling rain

3. Wind

Another natural element to consider is wind. The good news is that your paint will dry faster if humidity is low, but there is a breeze. However, high wind can cause dangerous situations on a ladder. There’s also the reality that wind can cause ripples in thick paint and will increase the amount of overspray headed down the street, especially when using a spray gun.

4. Thickness

brush applying thick yellow paint on exterior siding

Speaking to the thickness of the paint, thicker paint results in longer dry times. The type of application can affect the thickness. For example, spray guns offer several spray settings. Sponging, rolling, ragging, and using a paint brush all vary the thickness of the paint too. Consider thickness when deciding whether you will have adequate dry time before the rain pours down.

5. Primer

hand painting primer on house exterior

If your project requires primer, you have two timelines to contemplate. Primer is somewhat less forgiving than paint when it comes to applying the next coat without curing. Primer is essential to the success of some projects, so don’t rush it. Although it may dry within 30-60 minutes, allow at least three hours of reliable dry time in ideal conditions before applying another coat of primer or your first coat of latex paint.

6. Oil-Based Products

In contrast to latex primers and paints, oil-based products take longer to dry—much longer. Where latex may be dry to the touch and potentially ready to accept another coat in an hour, allow six to eight hours for oil-based paint.