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What is the best time of year to clean windows in Boise?

Short answer

Spring and early autumn are the two best windows in Boise. Spring, roughly April to early June, clears winter grime and tree pollen. Autumn, roughly September to late October, gets the glass clean before the weather closes in and before the first hard freeze, which NOAA data puts at a 50% chance by around 21 October. Avoid late May and June near the Boise River, when cottonwood seed fluff sticks to freshly cleaned wet glass.

Last reviewed 3 September 2026 by Perfect Shine Home Solutions, Kuna, Idaho. Serving the Treasure Valley since 2016.

Why spring works

Winter leaves a specific kind of film on Treasure Valley glass: road grit, wood smoke residue in the inversion months, and then a heavy pollen layer in April and May. Cleaning once that has finished falling gives you the longest clean stretch of the year and it is the point where the difference is most visible, because the light is getting longer.

Why autumn is the more important one

Autumn cleaning is maintenance rather than aesthetics. Getting organic residue and mineral spotting off before the glass spends four months wet and cold stops deposits from setting hard over winter. It also pairs naturally with the autumn gutter clean, and booking the two together on one visit costs less than two trips.

The cottonwood window to avoid

If you are in Eagle, Garden City, or anywhere along the Boise River and Eagle Island corridor, late May through June is cottonwood season. The seed fluff sticks to wet glass and to freshly cleaned frames, which means an exterior clean done in the middle of it is money spent twice. Book either side of it.

Summer is fine, with one caveat

There is nothing wrong with summer cleaning except that glass in direct sun dries faster than a squeegee can clear it, which is what causes streaking. Any competent crew works the shaded elevations first and follows the sun around the house. If you are doing it yourself, start early or work in the shade.

Winter

We do clean in winter, and interior work is unaffected. Exterior work needs the temperature above freezing for water to behave, so it becomes weather-dependent and we schedule it around the forecast rather than promising a date three weeks out.

Booking calendar for Treasure Valley exterior work

NOAA data puts Boise's first 32-degree frost at a 10% chance by 5 October and a 50% chance by 21 October.
SeasonWindowsGuttersPressure washing
Mar - MayBest window of the yearSpring checkSeason opens
Late May - JunAvoid near the river (cottonwood)Clear after cottonwood, river homesGood
Jul - AugFine, work the shadeQuietPeak season
Sep - OctSecond best windowThe important one, before first freezeSeason closes late Oct
Nov - FebInterior any time, exterior weather-dependentToo late, book earlierClosed

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Sources

Perfect Shine prices quoted on this page are our own published prices. Ranges described as typical reflect what Treasure Valley homeowners commonly pay and are not a quote.

Related questions

How often should windows be cleaned in the Treasure Valley?

Twice a year for most homes, spring and autumn. Once a year is acceptable if the house is sheltered and you are not particular. More than twice makes sense if you are on a busy road, near open farm ground, or your sprinklers hit the glass.

Can windows be cleaned in winter in Idaho?

Interior glass any time. Exterior work needs above-freezing temperatures, so it becomes weather-dependent from about November through February. We book it around the forecast rather than committing to a fixed date weeks out.

Should I clean windows before or after gutters?

Gutters first, then windows, if they are on separate visits. Clearing a gutter dislodges debris and dirty water that lands on the glass below. If we are doing both on one visit we sequence it that way automatically.

When should I book to have it done before guests arrive?

Two to three weeks out for a specific date, and more than that for the last two weeks of any month between April and October, which is when the calendar fills first.

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