Short answer
There’s no single best time of year to clean windows; glass gets dirty all year. Spring and summer bring pollen: the Met Office says tree pollen typically runs from late March to mid-May, grass pollen from mid-May until July, and weed pollen from the end of June to September. That’s when many homes notice a film on the glass.
What does pollen do to windows?
Pollen is fine dust from trees, grasses and weeds. It settles on glass, frames and sills, and when it gets damp from dew or light rain it can dry into a yellowish film. Homes near trees, hedges, fields or parks tend to see more of it. It isn’t harmful to your windows, but it does make them look dull.
When are the pollen seasons?
The Met Office gives three broad seasons for the UK:
- Tree pollen: typically from late March to mid-May.
- Grass pollen: from mid-May until July, with two peaks.
- Weed pollen: from the end of June to September.
Exact timings vary from year to year with the weather, and the Met Office publishes pollen forecasts during the season.
| Pollen | Typical season (Met Office) |
|---|---|
| Tree pollen | Late March to mid-May |
| Grass pollen | Mid-May until July |
| Weed pollen | End of June to September |
Should I wait until pollen season is over?
You don’t need to. If you’re on a regular round, the glass is rinsed every few weeks, so pollen doesn’t have time to build up into a heavy film. If you only want one clean a year, late summer, after the worst of the grass pollen, is a sensible choice, but it’s your call.
What about tree sap?
Some trees drop a sticky residue onto anything below them, including cars and windows. It’s often worst in summer. Pure water and a brush shift most of it, though heavy, old deposits can take more than one clean. If a tree overhangs your windows, tell me on the quote form.
What does each season bring?
- Spring: tree pollen, nesting birds, spring showers.
- Summer: grass pollen, sap, dust on dry days, and insects.
- Autumn: falling leaves, damp, and dirt washed down from frames and gutters.
- Winter: road spray, condensation inside, and low sun that shows every mark. Can windows be cleaned in the rain or winter? covers the weather.
Is spring cleaning the windows a good idea?
Many people like a fresh start in spring, when longer days show the dirt left by winter. It’s a good time for a one-off clean, especially if you’re not on a round. Just be aware that tree pollen may arrive soon after.
Why a regular round works across the seasons
A round evens out the seasons. Instead of one big clean when the glass looks bad, the windows are rinsed every few weeks, so pollen, sap and road film never get the chance to build up. That’s why I run outsides every 6 weeks. What happens on a regular round? explains it.
Does hay fever matter for the clean?
If you have hay fever, cleaner windows won’t change the pollen count outside, and I can’t claim they’ll help your symptoms. Keeping windows closed on high-pollen days is what the Met Office and health services usually suggest; it also stops water getting in while I clean.
What about birds in spring and summer?
Spring and summer also bring more birds nesting under eaves and around gutters, and with them more droppings on glass and sills below. Bird mess is best not left to bake on in the sun. Pure water and a soft brush shift most of it; older marks may take more than one clean.
What about autumn leaves?
In autumn, wet leaves stick to glass, sills and frames, and leave brown marks as they rot. Gutters full of leaves can also overflow and send dirty water down the front of the house. I clean glass, frames and sills, not gutters, but if overflowing gutters are marking your windows, it’s worth getting them cleared.
And winter?
Winter brings road spray on front windows, condensation inside, and low sun that shows every streak. It’s also when clean glass makes the most difference, because you want every bit of daylight.
Common questions
Do windows get dirtier near fields or parks?
Often, yes, because there’s more pollen and dust around. How much depends on wind direction and how close the green space is.
Is autumn a bad time for a clean?
No. Falling leaves and damp can mark frames, but the glass still benefits.
When should I start a regular round?
Whenever suits you. There’s no wrong month.
Does pollen stain uPVC frames?
It can leave a yellowish film on white frames, which usually comes off with a brush and rinse.
