It’s crucial that you get the weather conditions right when painting your home exterior. Naturally, you can’t paint in the rain, but what about low temperatures? Many people assume that it will be fine as long as it is dry, but that isn’t the case. In fact, the temperature has a big impact on the way that the paint applies and cures on your walls and if it is too cold, the finish will be affected.
As a general rule, you should avoid painting when the temperature is less than 50ºF (10ºC). If you paint when it is too cold, the paint will not adhere to the surface properly and it will peel prematurely. Humidity and rapid changes in temperature also damage paintwork, so these factors also need to be considered.
The longevity of your paintwork depends largely on the conditions when it is applied, especially the temperature. If you want your home exterior to stay protected for years to come, it’s important to know when it is too cold to paint. Read on to find out more about painting outside in cold temperatures.
Can you Paint in the Winter Outside?
In general, you should avoid painting in the winter months. In colder conditions, paint is less viscous and this means that it takes longer to cover the surface and dry properly, which leads to unsightly brush strokes appearing on your walls. It can also lead to other problems with the finish, like drips.
However, if you do need to paint outside in the winter, it is important to buy the right products. There are specifically formulated paints that are more effective at lower temperatures.
How Does Temperature Affect Paint Outside?
The temperature affects paint outside in a number of ways. First, it can have a significant effect on viscosity. In warmer conditions, paint is more liquid and this makes it flow over a surface much more easily. This also means that you need fewer coats to adequately cover a wall and this creates a neater finish.
In colder conditions, paint is very viscous and this prevents it from flowing as freely as normal and the slow drying time makes the application process problematic. As mentioned above, cold temperatures make paint take longer to dry and your brush strokes will show up if you don’t wait for sufficient drying time between coats.
Check out our article “How Long Does It Take for Paint to Dry Outside?” for more drying information.
How Does Humidity Affect Paint Outside?
Humidity also has a role to play. In high humidity, the paint will take longer to dry and this can lead to moisture seeping back into the surface. This causes bubbling and peeling, which becomes very noticeable over time.
Humidity also affects paint viscosity; water molecules cause it to be more fluid. The result is that paint runs off the surface much more easily if you are painting outside in humid conditions. This increases the likelihood of drips and makes it much harder to achieve an even finish.
High humidity levels also lead to leaching in latex and oil-based paints. This is when patches of white or brown discoloration appear on the surface and ruin the finish. The combined impact of temperature and humidity can lead to a big difference in the way that your paint looks once it is dry, so it is important to measure both factors.
What if I Keep the Paint Warm, Does it Help?
Keeping the paint warm seems like a logical solution to many of the problems caused by low temperatures, but will it really help?
Heating paint can help to make it less viscous so it is easier to apply. The easiest and safest way to heat paint to the ideal temperature is to put it into a bucket of warm water for around 15 to 20 minutes. Although this helps to an extent, you will still have problems because the temperature of the surface that you are painting onto is still very low. The paint will not dry effectively in especially low temperatures, even if you heat it up.
In some cases, you can use plastic sheeting to create a bubble around the home and then use a small space heater to create a good temperature for painting. However, it can be difficult to maintain the right temperature while the paint dries and cures.
Technically, heating paint is an option, but it is best to ensure that the ambient temperature of the paint and the surface are correct before painting.
What is the Ideal Temperature and Humidity for Exterior Painting?
Ideally, you should not paint in temperatures under 50°F or 10°C. The ideal humidity for exterior painting is between 40 and 60 percent relative humidity (RH).
Different paints are best suited to different temperatures. The ideal temperature for painting with latex paint is somewhere between 50-70°F (10-20ºC). However, oil paint is more flexible and will apply well between 49-90°F (9.5-30ºC). Acrylic paint is best applied at temperatures of between 60-85°F (15-30ºC) and alkyd paint can be applied at temperatures between 46-95°F (8.5-35ºC).
If you do want to paint in the winter, there are specific latex paints that are designed for use at temperatures as low as 36°F (2.2ºC). These will cure properly even in cold weather, so the finish on your paint is not affected.
What is the Best Exterior Paint for Cold Weather?
Different paints are formulated to work at different temperatures, so the type of paint that you use is very important. Latex paints are generally preferable because they dry quickly and become less viscous in lower temperatures. Latex options such as FlexTemp Exterior Acrylic Latex Paint by Sherwin Williams, this paint can be applied in extreme temperatures ranging from 35° F to 120° F, really an all-around temperature option for great adherence.
Oil-based paints are also good for painting wood as they can be used in colder temperatures. One of the best exterior oil paints on the market right now is the RUST-OLEUM Exterior Mildew Performance Paint.
When purchasing paint products, always check the guidelines on the can and it will tell you the optimum temperature to apply it.
So, What Happens if I Do Paint in Cold Weather?
In an ideal world, you should wait until the weather warms up before you tackle any exterior painting jobs. However, there are some circumstances when you need to paint your home exterior right away to ensure that it is protected from the elements.
If you paint in cold weather, the paint is likely to dry slower than usual. This means that the risk of brush strokes, dragging, and drips are increased. The surface of the paint stays wet for much longer too, so more bugs and dust can get into the surface, causing even more damage to the finish. Depending on the type of paint that you use, you may also experience problems with leaching, leaving brown and white spots on the surface of your paint.
If the temperature is only a few degrees lower than ideal, you should be fine. However, if the temperature is close to zero, it is best to avoid painting altogether. If you do need to paint in a hurry, it’s important that you use the right products and consider heating the paint gently beforehand. You can also try using plastic sheeting and heaters to create a warm bubble around the home and maintain the temperature.
Cold Temperatures Exterior Painting FAQs
Can I Paint my House When it is snowing?
Painting your home exterior in the snow will cause a lot of problems. Firstly, you have all of the issues with the temperature discussed above. If it is cold enough for snow to form, the finish on the paint will be seriously damaged. Secondly, the moisture from the snow will damage the paint too. It will not dry properly and if the snow is particularly heavy, the paint will start to run.
Can my paint freeze inside the can?
Yes, paint can freeze in the can. If it is left at temperatures below zero for too long, it will freeze. Storing paint properly is crucial, especially in the winter. Try to avoid storing it in an unheated garage or shed. These conditions can damage the properties of the paint and cause problems when you need to use it later on, especially if there is condensation inside the can when you take it out.
Can I use paint after it freezes?
If you have some paint that has frozen, you can thaw it out. However, you may not always be able to use it. To thaw out your paint, leave it at room temperature and allow the ice to thaw naturally. Heating paint too quickly to thaw it could cause further damage and make it unusable.
Once the paint has been thawed fully, give it a good stir and see how it looks. If it does not look grainy or clumpy and there are no foul odors, the paint should be fine to use. However, if the paint appears lumpy or the colors have changed in some way, the chemical makeup has been affected by the freezing process and it should not be used.
If you are in doubt about painting outside in the winter, it’s best to check the manufacturer’s guidelines. All paint products will have information about the ideal application temperatures and if you follow those instructions, you can avoid any problems.
Jamie is the founder of The Backyard Pros. When he was 15 years old he started working at a garden centre helping people buy plants, gardening products, and lawn care products. He has real estate experience and he is a home owner. Jamie loves backyard projects, refinishing furniture, and enjoys sharing his knowledge online.