When are cockroaches most active?

It’s easy to assume cockroaches are infesting our homes all year round. While the cooler months may offer some respite, entomologist Graeme Smith says cockroaches can invade kitchens and industrial spaces at any time of the year. That’s because they like warm and humid places no matter what the weather’s like. The warmer months are their chief breeding season, however, so it pays to understand their life cycle.

“When the weather gets cool, the cockroaches are much less active,” says Smith. “They almost go dormant, even though they don’t necessarily die out.”

Know your enemy

The movements of cockroaches can be broken down into the two main types of cockroaches encountered in this country:

German cockroaches

These small, brown cockroaches “are very prevalent in industrial situations like commercial kitchens and bakeries, on planes and trains, and things like that,” explains Smith.

If a dwelling or premises is heated and air-conditioned, the cockroach can be a year-round visitor — but will still be more common in summer. Their numbers also vary depending on location.

Larger American cockroaches

These larger cockroaches, like the  smoky brown species, are more commonly found outdoors. They’re slower-breeding but — put down that sandwich if you’re going to read on — it’s worth knowing they like to breed in drains and occasionally in kitchens.

“Mostly they come into kitchens from outside, and they’re the ones that freak people out the most. They can fly as well,” says Smith.

As the weather warms up, they breed more and you’ll get more of them. “Up in Cairns they might be there almost the whole year round, but in the middle of winter they’ll drop off,” says Smith.

Find out how to get rid of cockroaches here.

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Fun Facts


Believe it or not, even the cockroach can make a pet for the truly adventurous. The heaviest of the species is the giant burrowing cockroach, it can grow to 80mm in length and is odourless and clean.