For painting projects both inside and outside, temperature plays a significant role in determining your success. And when we think about painting outdoors, the image of a sunny day is often the first thing that comes to mind. However, what if you don’t have the luxury of that kind of weather? When is it too cold to paint outside?
Below we’ll answer that question, explain how climate conditions impact your paint project, and share tips on how you can best paint outdoors in cold temperatures.
How Temperature Impacts Your Finish
The best range of temperatures will depend on what kind of paint you’re using when painting outside.
For latex paint, the range is 50 to 70 degrees Fahrenheit.
And with oil-based paints, it’s 45 to 90 degrees Fahrenheit.
Other Factors to Consider When Painting Outdoors
Because air and surface air temperature can swing drastically, it’s essential to keep this in mind. Some exterior surfaces may require a day or two to warm up after cold-weather properly. And since paints, on average, need one to a couple of days to fully cure, it’s best to check the weather conditions for the day after you’ve finished painting to make sure the temperature won’t drastically change while your stain or paint’s drying.
When It’s Too Cold
Whenever outside temperatures drop below 55 degrees Fahrenheit, it will interfere with the curing process. And when paint takes a longer time to dry, the surface will stay wet longer, which can attract dirt, insects, grime, and other types of debris. Cold weather will also reduce your paint’s overall life expectancy.
Oil-based paints will thicken in cold weather, which causes heavier application, stiffer brushing, and much less coverage per gallon.
When It’s Too Hot
There are also days when it can be too hot to paint, such as when temperatures reach 90 degrees Fahrenheit and above. Excess heat will cause paint to dry too quickly and compromise adhesion. Blisters and bubbles also begin to form in the paint, and once it cures, the paint will start peeling from the surface.
While sunny days may not reach temperatures as high as 90 degrees Fahrenheit, direct sunlight can also cause your paint to dry too quickly. And experts recommend that when painting, you try to follow the sun’s shadow around your home.
Then you need to allow the paint to dry to the touch (if painting something moveable like furniture) before relocating it indoors before the cooler temperatures arrive along with humidity factors like morning dew.
That said, there is an exception to this rule. If you have cooler temperatures such as 32-60 degrees Fahrenheit, then direct sunlight can be a benefit since the surface temperature may balance out the heat from the direct sunlight.
Another factor to look out for is humidity, which measures how much water vapor is in the air. Too much moisture will result in water vapor getting into your freshly painted surface. The ideal level of humidity when painting outdoors is 40 to 70 percent.
Painting in humidity that’s too high may result in:
- It can compromise your paint’s protective qualities.
- Cause leaching is a condition in which brown or white discoloration forms on the surface of oil or latex-based paints.
- Slow the evaporation of moisture from the solvents in the paint. This causes longer cure times and reduces the quality of the finish.
Also, when painting the surface of wood, humidity is very important since wood absorbs moisture from the air, which will cause paint to peel or bubble by impeding adhesion.
Humidity control is one of the best reasons to consider painting indoors if possible, as you can both control temperature and humidity with devices like a humidifier and an air conditioner.
The Best Temperature Range for Painting Outdoors
Your ideal outdoor painting temperatures range from 60 to 85 degrees Fahrenheit with little wind and humidity levels within the 40 to 70 percent range.
The Ideal Paint for Painting Outside
If you need to paint in temperatures below 50 degrees Fahrenheit, your best bet is to find a latex paint specifically formulated to perform in temps as low as 36 degrees Fahrenheit. Such a paint will have coalescing agents that beef up the paint’s curing attributes when exposed to low temperatures.
Tips and Strategies for Painting in Cold Temperatures
Here are a few tips to help you paint better in colder temperatures.
Since your paint will be thicker, you want to use stiffer brushes made with polyester, nylon, or Chinex bristles, which work very well with thicker paints.
Check Surface Temperatures
Many make the mistake of thinking the surface temperature of what they are painting will match the atmospheric temperature. However, you could have air that’s 55 degrees Fahrenheit while your surface temperature is 40 degrees Fahrenheit, then your cure time will be determined mainly by that surface temperature.
One way to check your surface temperature is to get an infrared thermometer, as used by professional painters. They’re not terribly expensive, with decent models selling for around $20-$50. One of these thermometers can save you a lot of hassle down the road.
Make a Painting Bubble
This may sound like a crazy idea, but you can literally build yourself a bubble over the area you will paint. You would need 4 to 6-millimeter plater sheeting with a framework of zip poles, 2x4s, or scaffolding to pull this off. You can also buy unique tents for this purpose. The bubble or tent should be totally enclosed, and you can even bring in a space heater to raise the inside temperature to where you want it.
You must maintain your temperature in the bubble as the paint cures. And it’s also important to have good ventilation and never leave your space heater unattended.
Obviously, this is a much more complex solution if you’re painting a house.
Is Paint That’s Been Frozen Unusable?
If you have paint that’s been sitting outside and had been frozen a few times, it might not be usable. Of course, this depends on a few things, such as if it’s oil or water-based. It is not usable if the paint is lumpy and cannot mix to a smooth consistency.
That condition indicates your paint lost the ability to emulsive, meaning it can no longer cure properly because of the water content present in water-based paint. Most freeze at 32 degrees Fahrenheit. However, oil-based paint does not freeze as quickly.
Recoating in Cold Temperatures
Since colder weather will slow down drying time for all paints, this also means that your timeline for recoating will also be extended. For Instance, at 73 degrees Fahrenheit, it’s usually safe to apply another coat after about four hours. Bu, at 50 degrees Fahrenheit, your recoat time is likely to extend to six or seven hours.
Also, if you’re using oil or alkyd paints, you may have to wait even longer. In some cases, this wait could be a full 48 hours. To prevent any issues, always adhere to the paint manufacturer’s recommendations regarding recoat times.
And please keep in mind that either shade or direct sunlight can cause differences in surface temperatures in different areas on a single structure, such as a home or mobile trailer.
While painting outdoors in cold temperatures isn’t ideal, it can be done up to a certain point. If you have time to wait for the best conditions, that would be the easiest approach, but if you have to work in temperatures below 50 degrees Fahrenheit, you have options to make achieving the perfect paint job doable. It’s just going to take more patience.