Does Mould Stop Growing When It Gets Cold?

Most people think of mould as a summer problem—sticky humidity, heavy storms, and musty basements. But mould doesn’t care about the forecast. Once it takes hold, it can keep growing long after the air turns cool and crisp.

In fact, cooler weather often works in mould’s favour. When moisture lingers and ventilation decreases, it can dig in deeper, lying in wait for the right conditions.

Mould doesn’t stop—it slows down

When temperatures drop, mould doesn’t die off. It simply becomes less active. Growth slows, but spores stay alive in a dormant state. As soon as heat and moisture return, those spores reactivate—sometimes spreading faster and more aggressively than before.

Poor ventilation makes it worse

In summer, open windows and fresh air help your home “breathe.” By fall and winter, houses are sealed tight to conserve heat, which locks in stale, damp air—perfect for mould growth.

Some of the highest-risk spots include:

• Attics and crawlspaces

• Basements with poor airflow

• Cottages or seasonal homes left closed up

• Closets and cabinets against exterior walls

Moisture is the real culprit

Cold weather doesn’t cause mould—moisture does. And fall brings plenty of opportunities for it to sneak in:

• Heavy autumn rain and roof leaks

• Rising indoor humidity in sealed homes

• Window condensation

• Piles of wet leaves around the foundation

If these issues go unchecked, mould won’t just linger through the cold months—it will thrive once indoor heat and moisture levels rise.

When to Call a Mold Removal Company

While you can take preventative steps at home, some mould problems require professional attention. A certified Mold Removal Company can:

• Identify hidden mould in walls, attics, and crawlspaces

• Safely remove active mould without spreading spores

• Treat underlying moisture issues to prevent future growth

• Provide guidance on maintaining a healthy, mould-free home

Scheduling a professional inspection before winter can save you time, money, and health risks, ensuring your home stays safe even as temperatures drop.

How to protect your home this fall

• Inspect basements, attics, and other risk areas before sealing up for winter

• Run dehumidifiers in damp spaces

• Keep vents open and ensure proper airflow

• Schedule a professional inspection if you’ve experienced leaks or water damage this year

At ACI Restoration, our experts specialize in spotting both active mould and hidden risks. A fall inspection can help you avoid winter headaches—and prevent mould from resurfacing in spring.