Guides

The Best Time of Year to Pressure Wash, by Climate

Why season matters more than people expect

Cleaning solutions need to stay wet to work. Surfaces need to be above freezing. Timber needs to dry before it can be sealed. Get the season wrong and you either get a worse result or you pay for work that has to be redone.

There is no single right month, because the constraint is different in each climate.

Cold winter climates: wait for spring

Chicago, Toronto, Montreal, Calgary, Boston, Denver, Stockholm, Copenhagen, Munich.

Book from late spring, once overnight temperatures stay reliably above freezing. Two reasons. Water left in mortar joints and concrete pores that then freezes will cause spalling, so cleaning in near freezing conditions can genuinely damage masonry. And the main thing you are removing is winter road salt and grit, so there is no point cleaning before the salt has stopped arriving.

The catch is that everyone wants the same six week window, so book early. In Calgary and similar the usable season is genuinely short.

Wet temperate climates: take the dry window

Seattle, Portland, Vancouver, Glasgow, Manchester, Dublin, Hamburg, Amsterdam, Bergen.

Aim for the driest stretch you get, typically late spring through early autumn. The problem here is moss and algae, and treatment needs the surface to stay dry long enough afterwards for the solution to finish working. Rain an hour after a soft wash dilutes and rinses it off before it has killed anything.

Timber work in particular needs a dry run of several days if you intend to seal it.

Hot dry climates: avoid peak summer

Phoenix, Las Vegas, Madrid, Marseille, Dallas, Austin.

Counterintuitively, high summer is the worst time. Surfaces get hot enough that cleaning solutions flash dry before they can act, which wastes the chemistry and can leave residue marks. Work autumn through spring, or early morning on shaded elevations.

Anyone willing to soft wash a south facing stucco wall at 2pm in July in Phoenix is not going to get a good result.

Humid subtropical: year round, with a rhythm

Miami, Houston, Atlanta, New Orleans, Charlotte, Nashville.

Growth is fast enough here that there is no off season. The useful pattern is to clean before the peak humidity rather than after, so late winter into spring, and treat biologically rather than just rinsing, because recontamination is quick.

Atlanta and much of the south east have a distinct pollen season. Wait until it has finished or you will be cleaning twice.

Booking practicalities

The busiest weeks everywhere are the first genuinely warm weeks of spring, when everyone looks at their driveway at once. If your timing is flexible, the shoulder seasons get you faster scheduling.

Commercial frontage is different: it is usually done very early morning regardless of season, because it has to happen before opening.