The best time to clean windows in Michigan is late spring, once the maple and oak pollen has dropped, with a second cleaning in the fall after the leaves are down. The outside season here runs March through November. In winter, rinse water freezes on the glass, so outside work waits and inside glass gets cleaned any month of the year. If you're doing it yourself, pick a time of day when the glass is in shade.
That's the short answer. The rest of this post is why each date falls where it does.
When the outside season opens
March. Before that, it's too cold for water. Detroit Metro averages a low of 19.2 degrees in January and 20.8 in February in the National Weather Service's 1991–2020 normals. Below freezing, rinse water turns to ice on the glass, the siding and the front walk, so we stop booking outside work once the overnight lows drop and start again in spring.
March itself is a borderline month. Its average low is 28.6 degrees, below freezing, and its average high is 45.9. An outside cleaning in March goes on a day that warms up, and if a date is too cold, we'll tell you at booking that it needs to wait.
The dirt on the glass in March comes from winter. The film on storm doors and lower windows is road salt, thrown up by traffic and by your own driveway. Water takes it off easily. A dry cloth just smears it.
Why late spring is the one to book
If you only clean the outside once a year, make it late spring. That one visit clears a winter of road salt film and a spring of pollen together.
The timing hangs on the trees. We see maple and oak pollen coat outside glass from late April into May. In Novi, oak pollen sits on everything for about three weeks in May, and it sticks because it's wet when it lands. A cleaning done just before the pollen won't last. Wait until it's done, in late May or June, and the cleaning holds.
Early spring has its place. A March or April cleaning gets the salt film off early, which suits houses that face a busy salted road. Just expect to see pollen on the glass again in May.
Spring rain is no reason to wait
Spring is wet here. May is the wettest month of the year at Detroit Metro, with 3.72 inches of precipitation in the 1991–2020 normals, and April brings 3.26. It's tempting to hold off on the windows until the rain lets up.
Rain on its own rarely spots glass. The spots come from rain running off a dirty frame, from gutters overflowing across a window, or from sprinklers, which carry the most minerals. That's why Marvin says to clean the frames, grids, tracks and hardware first and the glass last. Clean frames give the rain nothing to carry down the pane.
We clean outside glass with deionized pure water on a water-fed pole. Nothing is dissolved in the water, so nothing is left on the glass when it dries, and we clean the frames on the same pass.
Summer, if sprinklers hit the glass
Summer is sprinkler season, and sprinkler spray is the most common cause of permanent window damage we see on Michigan homes. A head that hits a first-floor window puts mineral-heavy water on the glass, the sun dries it, and it happens again every other morning all summer. Left for a few seasons, the minerals etch the glass, and etching can't be cleaned off.
Walk your irrigation zones while they run and turn any head that sprays the house. Houses with sprinklers hitting the glass do better with a third cleaning each year.
Fall, after the leaves and before the cold
The fall cleaning works best once the trees over the house are bare. MSU Extension says Michigan's fall color starts in the Upper Peninsula in mid to late September and ends in late October in southeast Michigan. Leaves that come down after a cleaning leave stains on the glass and the sills.
The gutters go first. Grit from a gutter cleaning can land on clean glass, so if you're having both done, book them together and we'll do the gutters before the windows.
The cold sets the other end. Detroit Metro's average low is 33.9 degrees in November and 25.3 in December. November is our last outside month, so for a lot of Metro Detroit, the fall window is late October into November. If you have young trees and an open lot, early fall works fine. In Birmingham, under the big street trees, it pays to wait until they're bare.
The best time of day: shade
For a DIY cleaning, the time of day matters as much as the month. Marvin says to wash windows when the sun isn't shining directly on them, because sun speeds up the drying of the washing solution, which can leave streaks or spots. Milgard's care guide gives the same advice: clean glass during cooler temperatures, out of direct sunlight.
The sun moves around the house, so plan by which way each window faces:
East-facing windows in the afternoon, once the sun has moved off them.
West-facing windows in the morning.
South-facing windows on an overcast day, or early and late in the day.
North-facing windows any time.
An overcast spring day is the easiest of all. Every side of the house is in shade at once.
A Michigan window calendar
Here's the year in one table, from what's on the glass to when we can clean it.
Month | Outside glass | Inside glass | What's on the glass |
|---|---|---|---|
January and February | Waits for spring | Easiest months to book | Furnace and fireplace film inside |
March | Season opens on days above freezing | Any time | Road salt film on storm doors and lower panes |
April | Open | Any time | Spring rain, and pollen starts late in the month |
May | Open | Any time | Maple and oak pollen |
Late May and June | The main spring cleaning | Any time | Pollen done, sprinklers starting |
July and August | Open | Any time | Sprinkler spots on lower panes |
September and October | Open | Any time | Leaves coming down |
November | Last outside month | Any time | Gutters first, then windows |
December | Waits for March | Any time | Inside before the holidays |
Two cleanings a year, or three
Two suits a typical house here: late spring after the pollen, and fall after the leaves. Marvin says once or twice a year, with spring and fall the best seasons. Houses with sprinklers hitting the glass, mature trees close to the house or a busy salted road out front do better on three.
The inside can follow its own schedule, and winter is a good time for it. In Northville, the outside books up in two waves, spring after the pollen and fall before the holidays, while the inside runs all year.
If you'd rather do some of it yourself, our guides to cleaning window screens and cleaning window tracks cover the parts around the glass. Everything that comes with a visit from us is on our residential window cleaning page.
Questions people ask
What month is best for cleaning windows in Michigan?
Late May or June, once the maple and oak pollen has dropped. A cleaning then clears the winter road salt film and the spring pollen in one visit, and it stays clean longer than one done before the pollen. If you want a second cleaning, book it for the fall, once the leaves are down.
Is it better to wash windows in the morning or the afternoon?
It depends on which way the window faces. Clean east-facing glass in the afternoon and west-facing glass in the morning, so the sun isn't on the pane while you work. Direct sun dries the cleaning solution before you can wipe it off, and that can leave streaks. North-facing windows can be done any time.
Can you clean outside windows when it's cold?
Not once it's below freezing. Water freezes on the glass before it can be wiped or dried, and it freezes on siding, steps and walks too. In Michigan, outside window cleaning runs March through November, and inside glass can be cleaned any month of the year, including the coldest weeks of winter.
Should I clean windows in spring or fall?
Spring, if you only do one. A late spring cleaning takes off the road salt film winter leaves on storm doors and lower panes, along with the spring pollen. Fall makes a good second cleaning, once the trees over the house are bare and the gutters are clear, so leaves and grit don't land on clean glass.
Get a quote
Spring dates fill first once the pollen is done. Send your address and a rough window count through Get a Free Quote, and we'll price the house and put you on the schedule for after the pollen.
