Cleaning During Ontario's Summer Heat & Humidity
Ontario summers — particularly July and August in the GTA, Hamilton, Ottawa, and eastern Ontario — bring high humidity that creates specific home maintenance and cleaning challenges not present in other seasons. Understanding these challenges helps you keep your home healthier through the hot months.
Humidity and Mould
Ontario summer relative humidity regularly exceeds 70–80% during hot spells. At these levels, any cool surface (poorly ventilated bathrooms, basement walls, around air conditioning vents) can develop condensation that supports mould growth. Keep your air conditioner running to maintain indoor humidity below 50%. Check bathroom ceilings, basement walls, and window frames during humid stretches for early mould signs — a small spot caught early is far easier to address than a growing colony.
Air Conditioning Maintenance
Your central air or window AC unit circulates air through a filter that accumulates dust, pollen, and particulate. Check and replace filters monthly during summer cooling season. The exterior condenser unit benefits from an annual cleaning — clear plant growth, leaves, and debris from around the unit to maintain efficiency.
Kitchen During Heat
Hot weather accelerates food spoilage — clean the fridge more frequently (wipe down produce drawers weekly, not monthly) and keep the counter clean of food residue to avoid attracting pests. Flies and fruit flies appear faster in summer heat; a clean kitchen without open food is your best defence.
Summer Cleaning Schedule Adjustment
Consider adding a bathroom deep clean to your July or August schedule specifically targeting mildew prevention. Tile grout is the primary mould entry point in Ontario summer bathrooms — a thorough grout scrub during peak humidity season prevents the winter mould problem before it starts.