Long Island Algae Season: When to Wash Your House
Algae grows when it's humid and warm. On Long Island, that's April through October. Here's when to schedule a wash for the best result, and when to hold off.
March to early April: pre-season
This is our busiest period and for good reason. The algae that grew all summer and fall is dormant but visible. A wash now catches it before spring humidity lets it explode, and your house looks clean for the first BBQ of the year. Book 3 to 6 weeks out.
May to June: prime time
Warm days, predictable dry stretches, long daylight. Every surface washes and dries well. If you're doing a full-property service (house + roof + driveway), this is ideal. Book 4 to 8 weeks out.
July to August: works, but hot
Washing is fine but crews move slower in 90-degree heat and some chemistry flashes off too fast on hot siding. We start earlier (6:30 AM crew arrival) in these months. Book 2 to 4 weeks out.
September to October: second best
Humidity drops, temps are perfect, kids are back in school, and algae from the summer is at its most visible. Our second-busiest window. Book 2 to 4 weeks out.
November to February: off-season
We still wash roofs and commercial work through the winter because biocide works down to about 40 degrees. Residential siding is paused when temps drop under 45 consistently — the chemistry dwell time gets unreliable. If you call us in January for a house wash, we'll tell you the truth and schedule March.