Spring and fall are peak seasons for comfort; winter can mean shorter wait times if your crew uses cold-weather products. Browse all guides →
Quick answer: best seasons in Ontario
Most Mississauga homeowners schedule window replacement in late spring (April–June) or early fall (September–October) for mild weather and comfortable curing temperatures.
There is no single “wrong” month — professional installers work year-round. The best time is when you notice failed seals, drafts, or difficulty operating units, and when you can book a crew before peak-season backlogs.
Spring (April–June)
- Ideal temperatures for sealants and exterior finishing
- Easier to spot drafts after winter
- Longer daylight for multi-window projects
- Book early — this is the busiest season
Fall (September–October)
- Comfortable working weather before winter
- Address summer heat gain issues before next season
- Good availability if you book before August rush
Summer & winter
Summer installs are common; crews manage heat with one-opening-at-a-time methods. Winter installs are viable with cold-rated sealants — often shorter lead times in January and February. See our winter guide for cold-weather details.