"No point washing the windows, it's going to rain." The most durable myth in the trade, and wrong in most cases. Here is the honest version — without the sales line that we work in any weather, and without cancelling at the first drop.
Why rain does not ruin a clean
A properly cleaned window is a window stripped of its film of dirt. Rain is largely clean water. On clean glass it dries leaving little or nothing. On dirty glass it dissolves the settled dust and, as it dries, leaves the familiar grey streaks.
In other words: rain does not soil clean windows, it soils dirty ones. That is itself an argument for regular maintenance — the less deposit there is, the fewer marks rain leaves.
One nuance: alongside a busy road, rain throws road dust onto the lower part of the glazing. It is not the rain that soils, it is the spray, and it mainly affects the first metre above ground.
What genuinely stops the work
Wind. The number one criterion as soon as height is involved. A ten-metre water-fed pole becomes hard to control long before the wind feels dramatic at ground level. On a platform or ladder, wind is a pure safety matter. A job at height stops for wind, not for rain.
Frost. Below zero, water freezes on the glass and on the sills. You can neither squeegee properly nor let it dry, and the ground becomes dangerously slippery. Exterior work becomes impractical or unsafe.
Thunderstorms. Carbon pole, metal structure, height: no discussion.
Prolonged driving rain. Not because the result suffers, but because equipment gets soaked and an interior cannot be protected properly with windows open.
Snow and ice underfoot. A matter of access and stability, not of glass.
What about winter?
The Belgian winter does not rule out window cleaning. It constrains it.
Frost-free days — the majority of winter days in most Belgian regions — allow normal exterior work with a few adaptations: products suited to low temperatures, slower drying, a shorter working day because of the light.
Winter even has two overlooked advantages. The glass is dirtier, so the difference after cleaning is more visible. And artificial light shows everything: a business open after dark has its glazing lit at a raking angle that highlights every mark. It is precisely the season when a clean storefront stands out most.
Conversely, full summer sun is not ideal: the water dries before it can be squeegeed and leaves marks. The best weather for cleaning windows is overcast and mild — not bright sunshine.
Our decision rules
We do not cancel because it rains. We postpone when:
- wind makes work at height imprudent;
- it is freezing, or about to freeze during the visit;
- a thunderstorm is under way or imminent;
- ice or snow makes access unsafe.
When a postponement is needed, it is announced as early as possible and a new slot is proposed. A postponement is not turned into a surprise charge.
What you can do
- Do not judge the result in full sun and against the light within the hour: slightly damp glass reads badly. Look in diffuse light.
- Flag glazing exposed to road spray. It often needs a different rhythm from the rest.
- If you have the choice, plan a visit at the start of winter, after leaf fall and before hard frost.
FAQ
Is there any point if it rains tomorrow? Yes. Rain barely soils clean glass; it soils dust-covered glass considerably.
Do you work in freezing weather? Not outdoors. Water freezes on the glass and the ground becomes dangerous. Interior work remains possible.
Is a weather postponement charged? No. It is our technical decision, not a service rendered.
When is the best time to clean windows? Overcast, without strong wind and without frost. Bright sun is a poor moment.