Summer Piano Care in Ontario: The Season Nobody Warns You About

Everyone knows winter is hard on a piano — furnace air, cracked soundboards, the works. Fewer people realize that summer does the opposite damage, and the swing between the two is what actually ages the instrument. Ontario's July and August push indoor humidity into the 60s and 70s, and a piano responds within days: keys that stick or return slowly, pitch drifting slightly sharp, a tone gone dull and a touch gone sluggish. Here's what's happening, the number to watch, and the summer routine that pairs with the winter one.

What humid air does to a piano

Wood absorbs moisture. The soundboard swells and its crown rises, pushing string tension up — the piano goes sharp, unevenly, because different sections respond differently. The wooden keys swell and the felt bushings inside them tighten around their guide pins — keys drag and stick (the summer version of sticky keys, which vanishes in October and returns every July). Action felts soften and absorb moisture, so the touch goes spongy and hammers lose their crispness; the tone dulls. Sustained damp also lets rust start on strings and pins, and — in the worst cases — invites mould into felt.

None of this is catastrophic in one summer. The damage is cumulative: every swell-and-shrink cycle works the glue joints, the board, and the pin grip. A piano that lives through wide seasonal swings for thirty years is the one with the loose pins and the cracks. Steadiness is the whole game.

The number: stay under 60%

A $20 hygrometer near the piano is the summer routine's only equipment. The piano's happy band is 40–50%; 60% is the line where damp starts doing measurable harm. Ontario homes without air conditioning routinely sit at 65–75% in a humid spell.

Air conditioning naturally dehumidifies, which is why air-conditioned rooms often need nothing more — check the hygrometer and you may be done. Rooms without AC, and lower-level rooms where damp pools, want a dehumidifier when readings climb past the mid-50s. Size it to the room and empty it — a full dehumidifier is décor. Lakeshore homes (Etobicoke, Pickering, Port Credit, the Beaches) see the widest swings and benefit most.

Placement still matters. Keep the piano off exterior walls that sweat in humid weather and away from windows opened for the breeze — a piano beside an open window in July lives in the outdoor climate.

The vacation mistake

The most common summer damage we see isn't from humid weather — it's from the house left closed up for two weeks in August with the AC off. Indoor humidity climbs into the 70s, the piano soaks, mould finds the felt, and the tuning is gone. If you're away, leave the AC on a moderate setting (26°C is fine — it's the dehumidifying that matters) or run the dehumidifier on a drain hose. Cottage pianos have this problem all summer and deserve their own honest conversation.

Tuning timing for summer

If the piano's due, tune once the humid season has arrived and settled — late June onward — rather than in the transitional weeks of May, when the soundboard is still moving. A piano that sounds fine in June and sour in August didn't get a bad tuning; it got a climate swing, which the winter–summer two-tuning rhythm exists to manage for grands and serious players. For most home pianos, one annual tuning in the season it's played most is still right — just keep the room steady so it holds. Book here.

And keep playing through the summer. Regular use keeps the action limber and keeps pests out of a quiet, felt-lined box.

Common questions

Why do my piano keys stick in summer?
Humid air swells the wooden keys and tightens the felt bushings around their guide pins. It usually reverses in fall; a dehumidifier or AC keeping the room under 60% prevents it, and a technician can ease the bushings if it's bad.

Does air conditioning help a piano?
Yes — AC dehumidifies as it cools, which is the part the piano cares about. An air-conditioned room often holds the 40–50% band naturally through summer; check with a hygrometer.

Should I tune my piano in summer or winter?
Either, once the season has settled — not during the spring or fall transitions. Grands and serious instruments benefit from both; most home pianos do fine with one, timed to when the piano's played most. Winter guide here.