Is your deck looking shabby? Beginning to gray or look old and worn? Cleaning and staining your deck are great ways to spruce it up and make it more appealing, plus it protects it from the elements. If you’re wondering what the best temperature for staining decks is, we’re here to help!
Temperature and humidity affect drying time, adhesion, and finish. For best results, the air and wood surface temperatures should be between 70°F and 75°F (21°C to 24°C) and humidity between 40% and 50%. Always read the label for the application instructions and temperature guidelines.
In this guide, we’ll explain the importance of temperature to exterior staining, the best degree range, and what time of day and year produce optimal results. We’ll discuss how sunlight affects stain application and look at 8 popular stains and their temperature requirements. By the end of the guide, you should better understand the effect of temperature and the sun on the application and adhesion of stain and be able to determine the best time of day, year, and temperature to stain your deck.
- How Important Are Exterior Stain Temperature Requirements?
- What Is the Best Temperature to Stain a Deck?
- When Is the Best Time to Stain a Deck?
- What Is the Best Weather to Stain a Deck?
- Can You Stain a Deck in the Sun?
- Popular Deck Stains Application Temperature
- Can Deck Stain Freeze?
How Important Are Exterior Stain Temperature Requirements?
Temperature is very important, as is humidity and weather, and all need to be considered when staining a deck. Weather is obvious, forecasts of rain or snow within 48 hours of staining can ruin the finish. Humidity affects drying times which can be an issue if precipitation is forecast before the stain fully dries.
Heat and cold affect the application of stain in a variety of ways and can cause problems later. They can also shorten the lifespan of the finish. Stain manufacturer’s temperature guidelines don’t just mean the air temperature but that of the wood surface too. A sunny day can push the wood surface out of the acceptable range even if the air stays within it. This can cause the stain to dry too quickly for even penetration and leave lap marks.
Stained surfaces need to stay within the prescribed range until the stain is fully cured. Night temperatures may stay within the approved range, but the dew point temperature may not. Dew is as much a concern to curing stain as rain. It can affect drying times, durability, and make the finish peel, flake, and look splotchy, so it is another temperature issue.
What Is the Best Temperature to Stain a Deck?
The acceptable temperature range to stain a deck, according to most stain manufacturers, is between 50°F (10°C) and 90°F (32°C). The temperature doesn’t just refer to the daytime highs and lows though but to the surface temperature of what is being stained or painted. For the best results, the wood temperature needs to stay within that range until it is fully cured.
The best temperature to stain a deck is 70°F (21°C) with a humidity of 40%, which allows for a 20° buffer between the accepted high and low temperatures. If the wood is too warm, the stain can dry too quickly causing uneven absorption, blotchy finish, and poor adhesion resulting in peeling and flaking. If it’s too cold, there is less evaporation which can lengthen the drying time and curing process, preventing proper adhesion and reducing durability.
If you live in an area where cold temperatures are common but still need to apply stain to protect a deck or other wood surface, 50°F (10°C) may be a dream come true! Temperatures between 40°F (4°C) and 50°F are acceptable provided rain or snow aren’t forecast.
Cool days tend to have lower humidity, so the stain will cure fully, just slower. The coldest the wood temperatures should be is 32°F (0°C) to 35°F (2C°). However, the stain may not fully cure until the wood warms up some.
When Is the Best Time to Stain a Deck?
The best time to stain a deck is when there are at least three to four dry days forecast in a row with highs and lows between 40°F (4°C) and 80°F (27°C). The manufacturer’s recommended range is 10° higher, but slower curing is better than too fast. Four days allow for cleaning, drying, and one coat to cure. A second can be applied once the first is dry to touch, often within 4-hours according to some manufacturers.
Time of Year
The best time of year generally depends on where the deck is located geographically. In some temperate regions, it is better to stain in the spring before the summer heat or fall winds, or hurricanes. In much of the U.S. and Canada, the summer is a favorite time to stain, although spring and early to mid-fall often have more comfortable temperatures. Some places, like mine, you stain whenever the window of opportunity knocks.
Low humidity is better than high temperatures for drying, and shade or cloud better than direct sun. A block of days without precipitation is, however, necessary for the best results. Days with light or no winds are also better for even curing too. Summer tends to be a high use time for decks, so staining in spring or fall may work better for you.
Time of Day
The best time of day depends on the deck’s location. Mornings tend to be better before the heat of the day moves in, although morning dew (if any) needs to dry. If the deck is in the morning sun and shaded in the afternoon, the afternoon will be ideal unless the wood temperature is pushing 85°F (29°C) or more.
It is best to apply stain when the sun is not directly on the wood. The sun can dry the stain too fast causing the bond to fail and the finish to look dull and blotchy. If the deck is always in the sun, consider staining late in the day or in the evening. Spotlights may be necessary, but if the forecast, temperature range, and the dew point are acceptable, a midnight rendezvous with a can of stain, brush, or roller is a good alternative.
What Is the Best Weather to Stain a Deck?
The best weather to stain a deck is when the forecast calls for 3 to 4 days without precipitation and the wood surface temperature and highs and lows ranging from 40°F (4°C) 80°F (27°C). Cloudy days with low humidity and calm winds are better than hot, windy, sunny days as direct sunlight and UV can damage the bond. A low dew-point temperature is also helpful to ensure the deck surface stays dry while it cures.
Can You Stain a Deck in the Sun?
Staining your deck in direct sunlight is problematic since it’s difficult to pick the deck up and move it to the shade. The solar heat can cause the wood temperature to rise above the air temp, which can make the stain dry too fast, resulting in lap marks. It also can prevent the stain from bonding to the wood properly, causing it to peel and flake.
In addition, the ideal relative humidity is 40% according to many manufacturers. Humidity higher than 70% speeds up the drying time and can dull the finish. If you must stain in direct sun, it is best to pick a day with temperatures around 70°F (21°C), humidity between 40% and 70%, and a low dew point. However, provided the temperature of the wood and air stay below 85°F (29°C) to 90°F (32°C), you can stain in the sun.
Popular Deck Stains Application Temperature
Different manufacturers recommend temperature ranges for their stains. While the general guidelines may be 50°F (10°C) to 90°F (32°C) for wood and air temperatures, humidity, wind, dew point, and precipitation are also important factors. It’s always best to read the stain label and even check out the manufacturer’s website for application temperatures and recommendations.
Some manufacturers provide more information than others. Here’s some helpful application temperature information for different popular stains:
Can Deck Stain Freeze?
The type of base that a stain is made from determines if it can freeze or should be kept above freezing when stored. Water-based, water reducible alkyd-base, and modified oil-based stains will freeze and should be stored where they won’t. Oil-based stains won’t freeze and can be stored in heated or unheated buildings. Stored stains should be well shaken or stirred after storage to ensure they are fully mixed prior to use.
The best air and wood surface temperatures for staining a deck are between 70°F (21°C) and 75°F (24°C) with humidity between 40% and 50%. High humidity and conditions above 85°F (29°C) or below 40°F (4°C) can adversely affect absorption, adhesion, finish, and drying time.
The acceptable thermal range varies between manufacturers and even products within a brand, so it is important to review directions. Hopefully, you have a better understanding of why the temperature of the wood and air are important when applying stain, and also when to stain your deck for the best results.