The best time to stain a deck in Chattanooga

Short answer: September and October. Spring is our second choice. Midsummer and winter are the hardest. Here's why.

Stain needs dry wood and a few dry days

Stain has to soak into the wood. If the boards are wet, it can't. The U.S. Forest Products Laboratory, the government's wood research lab, says to let a deck dry for at least two warm, windy days after cleaning before you finish it¹. Home Depot's guide for pressure-treated wood says to let it dry 24 hours after cleaning². On a shady deck in a humid valley, we lean toward the longer number.

So the real question is: when does Chattanooga give you a run of dry days?

What the rainfall numbers say

Chattanooga averages about 55 inches of rain a year. The driest months on average are October (3.59 in.) and August (3.67 in.), and September and October have the fewest rainy days³.

5.02Jan

5.03Feb

5.34Mar

4.87Apr

3.94May

4.18Jun

5.08Jul

3.67Aug

4.23Sep

3.59Oct

4.80Nov

5.25Dec

That lines up with what we see on the job. Fall gives us dry spells, cooler afternoons and less direct heat on the boards. Stain that goes on in mild weather soaks in evenly instead of flashing dry on the surface.

Why not July?

July is one of the wettest months here on average, and pop-up afternoon storms are common. Hot boards also dry the stain too fast, which leaves lap marks. We still work in summer, but we start early, work in the shade side first, and watch the radar.

Why not winter?

Most stains need air and wood temperatures above about 50°F while they dry. Check the label of the product you're using. Winter days are short and the boards stay damp in the morning. We use winter for estimates and booking.

What about humidity?

Average humidity here is about 72%, and highest in September⁴. Humidity slows drying, which is one more reason we don't rush the wait between washing and staining.

Bottom line

• Book early for September and October. Those slots fill first.
• Spring works well too once the pollen settles.
• If your deck is peeling or gray now, get it on the calendar. Waiting another season usually means more prep and a bigger bill.

Sources

1. USDA Forest Products Lab — Finishes for Wood Decks (FinishLine, rev. 2013)
2. Home Depot — How to Stain Pressure-Treated Wood
3. NOAA NCEI — 1991–2020 monthly precipitation normals, Chattanooga airport (USW00013882)
4. Wikipedia — Chattanooga climate table (NOAA normals; humidity 1961–1990)