When Is the Best Time of Year to Clean My Roof in the Pacific Northwest?
In the Pacific Northwest, our climate is famous for its beauty — and infamous for how quickly it can ruin your roof. With high humidity, frequent rain, and shade from towering evergreens, moss doesn’t just grow here… it thrives.
So when should you clean your roof to stay ahead of the damage?
At Johnny Tsunami, we’ve cleaned thousands of roofs across Kitsap, King, and Pierce counties. Here’s what we recommend based on local climate patterns and decades of hands-on experience.
Why Moss Is a Year-Round Problem in the PNW
Moss and algae love:
- Cool, damp conditions
- Shady roofs (especially north-facing ones)
- Trapped debris like needles and leaves
This makes the PNW a moss hotspot, with active growth happening almost all year — but especially during spring and fall when moisture is high and temps are mild.
But here’s the trick most homeowners don’t know:
The Two Best Seasons for Roof Cleaning Are
Summer and Winter
Summer Cleaning = Prevent Winter Growth
Cleaning your roof in late spring or summer allows us to:
- Remove active moss before it dries out and embeds deeper
- Apply treatment that kills spores before fall rain returns
- Keep your roof clean and protected all winter long
Summer cleaning is preventative. It’s dry, safe to work, and sets your roof up for success through the moss-prone months.
Winter Cleaning = Catch It Before It Explodes
Most people assume winter is the worst time for roof cleaning. Not true. In the PNW, winter is when moss starts to spread fastest — because it’s cool, wet, and dark for months at a time.
Cleaning in late winter or early spring lets us:
- Remove the buildup before the spring surge of growth
- Prevent water retention that can damage shingles
- Prepare your roof for the sunnier, drier months
Our crews are trained and equipped to clean safely in winter, using soft wash systems and secure ladder setups — no harsh pressure washing, no damage.
What If You Wait Too Long?
Delaying roof cleaning until moss is fully grown out can lead to:
- Damaged shingles and shortened roof life
- Clogged gutters and water backups
- Increased risk of leaks, mold, and expensive repairs
That’s why we built our MX Plan — a recurring care package that auto-schedules roof and gutter maintenance based on your home’s needs and the season.
Our Recommendation for Homeowners in the PNW
- Summer Cleaning (May–August): Great for proactive care
- Winter Cleaning (December–March): Great for catching early spread
Spring/Fall: Still good, but timing is key — you’re either chasing moss or watching it re-grow
Johnny Tsunami’s Roof Cleaning Process
We use a specialized soft wash system designed specifically for the climate and roofing materials found in the Pacific Northwest. Our soft wash method combines eco-friendly solutions with low-pressure rinsing to safely eliminate moss, algae, and grime without causing damage to shingles or siding.
Unlike traditional pressure washing, our soft wash process preserves your roof’s integrity and lifespan, while delivering long-lasting results. Our technicians are highly trained in this system and follow strict safety protocols to ensure a thorough, damage-free clean every time.
Ready to Time Your Clean Right?
Whether you’re prepping for rain, protecting against moss, or just want your home to shine — our team is ready. Book your roof inspection and estimate with Johnny Tsunami today and get ahead of the season.
📞 Call us or request your quote online
