The short answer
Early fall is the most useful time for most homes. Cleaning gutters, roofs, walls and concrete before the rainy season, which usually runs roughly November to March, keeps winter runoff from carrying a summer's worth of dust and debris into new stains.
Spring is the second window. Once the rains taper off, a cleaning removes the mildew, algae and silt that winter left behind, and the property looks fresh for the long dry season. Summer and winter both work too, with a few adjustments.
There is no bad month in a mild climate like ours. The real question is what you want the cleaning to accomplish and what is likely to dirty the property again soon after.
Fall: get ahead of the rain
By September and October, LA properties carry months of dust, pollen, leaf litter and tree drip. Gutters are often full. When the first real storm hits, all of that washes down walls and across concrete at once and settles in low spots.
Fall is also Santa Ana season, and those dry winds, which can blow roughly from fall through spring, leave a coat of dust and debris on everything. It can make sense to wait until a wind event passes before you book, so you are not cleaning just before the next gust.
Winter: work between storms
Pressure washing in winter is fine on dry days. The main thing to avoid is cleaning right before a big storm. Freshly cleaned concrete is not harmed by rain, but mud and debris washing across it can undo some of the work.
Winter is a good time to deal with problems the rain reveals: green algae on north-facing walls, black mildew in shady side yards and slippery walkways. Those are safety issues as much as looks, so there is no reason to wait until spring for them.
Commercial properties often clean on a regular schedule year-round, and winter visits are part of that. Wet weather brings in more tracked mud at entries, so storefronts and walkways can need attention more, not less, during the rainy months.
Spring: reset and plan around jacaranda
Spring cleaning catches everything winter left behind. It is also the natural time for house washing, because walls are dry and the long sunny stretch ahead lets you enjoy the result.
If you have jacaranda trees nearby, think about timing. They usually bloom in late spring, and the fallen flowers stain concrete purple when they get crushed or rained on. Cleaning in the middle of the bloom can mean doing it twice. Many people sweep or blow blossoms off often during the season and book the deep cleaning once the trees finish.
Spring is also when pollen settles on cars, windows and patio furniture. A full house and patio wash after the heaviest pollen passes gives you a clean slate for outdoor living season.
Summer: early starts in the heat
Summer is busy for exterior cleaning, especially before parties and sales. The challenge is heat, particularly in the San Fernando Valley. Cleaning solution dries too fast on hot surfaces, which shortens dwell time and can leave streaks or spots. Hot stucco and dark concrete can also flash-dry before a full rinse.
The fix is simple. Start early in the morning, work in sections, keep surfaces wet and save the sunny side of the house for when it is in shade. Shaded areas and the coastal marine layer give a little more working time.
Timing around life events
Some of the best timing has nothing to do with weather. Clean a week or two before listing a home, before exterior painting so the paint bonds to a clean surface, before holiday gatherings and after construction or landscaping work.
If several areas need attention, booking them together saves money. Two services in one visit earn a 5% bundle discount and three or more earn 10%, on prices listed in our calculator as of October 2026. Same-day service is sometimes possible when the schedule allows, but spring and fall fill up, so plan a little ahead.
If you only clean once a year, early fall is usually the choice that protects your property most. If you clean twice, add spring. Busy commercial sites often benefit from more frequent visits, scheduled around their foot traffic.
Key points
The short answer
Early fall is the most useful time for most homes. Cleaning gutters, roofs, walls and concrete before the rainy season, which usually runs roughly November to March, keeps winter runoff from carrying a summer's worth of dust and debris into new stains.
Summer: early starts in the heat
Summer is busy for exterior cleaning, especially before parties and sales. The challenge is heat, particularly in the San Fernando Valley. Cleaning solution dries too fast on hot surfaces, which shortens dwell time and can leave streaks or spots. Hot stucco and dark concrete can also flash-dry before a full rinse.