5 Indoor Pests to Look Out For During Winter
With temperatures sliding and snowfall amounts rising, you might think winter is a quiet period for pests in Southern Ontario. While many of us encounter pests such as wasps, mites and more during the summer, the onset of winter can also be a big problem for keeping pests under control.
In fact, humans are not the only animals that prefer to stay inside during colder temperatures, as many rodents and insects make their way into our homes and businesses.
In this post, GreenLeaf’s professional pest removal experts break down what home and business owners should be looking out for when wintertime rolls around. If you suspect any of these pests are on your property, contact us today, and we will give you the professional pest control help you need.
1. Cockroaches
Cockroaches are found all over the world, including here in Canada and Ontario. With over 4000 different cockroach species across the globe, you might be understandably worried about them invading your home or business.
The good news is that only a handful of roaches are common in Ontario, including:
- German Cockroach
- Brown-Banded Cockroach
- Oriental Cockroach
- Pennsylvania Wood Cockroach
These cockroaches thrive in Ontario due to our cold climate.
Although many varieties of cockroach are extremely resourceful (some can even produce their own ‘antifreeze’ to survive temperatures as low as −122 °C), they still enjoy the warm indoors.
With temperatures regularly dropping below freezing and a sudden lack of food, cockroaches will seek to invade your home for food and shelter. They typically enter through human transport, such as a bag or garbage bin, or they manage to enter around windows and doors.
The problem with cockroaches in winter is that they are highly social pests. This means that once you have identified one in your home or business, you are quite likely to find more very soon.
Cockroaches are prolific breeders and can produce nearly 300 offspring in just one year, meaning pest control is a must even if you only see one inside your property. Ignoring them could result in food contamination and their spreading illness to others.
Learn more about cockroach removal, including what to do if you spot one inside your property.
2. Fleas
While you might associate fleas with pets and spending more time outdoors in the summer, fleas can also invade your home during the winter.
Just like cockroaches, fleas dislike the cold winter temperatures, as it slows down their reproduction rate and will typically kill most adult fleas. However, the problem isn’t necessarily the fleas outside, but rather the fleas that are already inside your property.
The drop in temperatures that occurs during late fall will send many adult fleas into your home, where they will lay eggs and reproduce. As capable jumpers that can leap 150 times their own height, fleas can travel very easily and will often use pets and even other pests to enter your home.
Getting rid of fleas should be a priority for any homeowner, even though they prefer biting pets over humans. Flea bites can make your pet very sick and even cause an allergic reaction.
Discover more about flea control in Toronto, including how you can take proactive steps to prevent a flea infestation.
3. Bed Bugs
Bed bugs are a commonly known indoor pest that infests many apartment and condo buildings across Southern Ontario, including cities like Toronto.
Keep an eye out for these 6-legged creatures if you can. However, at less than ¼ inch long and generally nocturnal (active at night), adult bed bugs can be difficult to identify until you have been bitten. Fortunately, bed bug bites do not transmit disease, but they will leave you with itchy, red, and painful marks on your skin.
Bed bugs feed off human blood and will prefer to bite during the night, which is why they’re called bed bugs. They don’t always live in your bed and can be found in all sorts of hidden nooks in your home, including picture frames, wallpaper and in your car.
Learn more about winter bed bug activity.
4. House Mice
Not all pests are bugs. In fact, some of the most harmful and common pests are rodents like house mice. Despite sounding local, house mice originate all the way from Central Asia, where they travelled over time to become widespread across Canada and the United States.
You may presume house mice are harmless and how similar they are to pet mice. However, house mice can be a nuisance and a health and safety hazard. This is because they enjoy eating human food, such as cereal, bread and other grain products, and easily transfer germs in doing so.
Just like many bugs, house mice are fast breeders, especially considering they are mammals. A typical female house mouse will have over 6 babies every three weeks, leading up to 35 offspring per year.
If you find house mice on your property, you must act quickly and contact a pest control company before their population is allowed to swell and do major damage to your home and health.
Despite their large numbers and size, it can be difficult to catch house mice as they are nocturnal. You can detect whether they are in your property by looking for signs such as droppings, gnaw marks or the appearance of hidden burrows in your walls and floors. If there are many mice in your home, you may begin to smell their urine, which helps them to communicate with others.
Don’t take chances or ignore the problem if you suspect rodent or insect infestation. Schedule a professional winter pest inspection right away and nip it in the bud.
5. Rats
Rats are another type of rodent that will invade your home or business during the cold winter months.
The Norway Rat is a common pest that infests many unprotected homes across Southern Ontario. Norway rats are much larger than a typical house mouse and usually reach about 8 inches in length, meaning they are easily visible if seen in daylight.
Norway rats are not picky when it comes to food either, and will gladly eat many different types of food across your home. They are particularly fond of dog food. This can be an issue as many homeowners feed their dog in an open dish on the floor. Therefore, if there is any leftover food in this dish, a rat can feed on it at night without the homeowner knowing.
Not only are rats a hygiene issue as they spread disease, but they are also renowned for their gnawing abilities, which can cause major structural damage to your property. If left alone, their population will increase, as does the risk of you, your family, or your customers catching a serious disease from them.
Prevention and Control Measures
Winter pest issues rarely start in January. They usually begin in late fall, when insects and rodents start looking for stable temperatures and reliable food sources. The good news is that a few focused habits can dramatically reduce your risk.
Start with exclusion. Small gaps around utility lines, dryer vents, and foundation cracks are open invitations for mice and overwintering insects. Seal openings with durable caulking or weather-resistant materials, and install door sweeps where light is visible under exterior doors.
Next, tighten up food and waste management:
- Store pantry items in sealed containers
- Wipe down cupboards and under appliances regularly
- Take garbage out consistently, especially before extended holiday travel
- Avoid leaving pet food out overnight
Clutter also plays a role. Storage rooms, basements, and garages packed with cardboard boxes create sheltered nesting zones. Replacing cardboard with plastic bins and keeping items elevated helps limit hiding spots.
Moisture control is another overlooked factor. Repair small plumbing leaks, run dehumidifiers in damp basements, and ensure proper attic ventilation. Many winter pests thrive in humid, undisturbed spaces.
If you notice droppings, scratching in walls, or repeat sightings, that is the time to bring in a professional. DIY traps may address what you see, but they rarely resolve the entry point or underlying nesting issue.
A licensed provider like GreenLeaf Pest Control can assess structural vulnerabilities, identify the species involved, and implement a targeted plan designed for long-term control rather than short-term relief.
Wildlife Entry into Homes
While insects and rodents get most of the attention, larger wildlife can also turn a warm home into winter shelter.
Squirrels
Eastern gray squirrels frequently access attics through roof vents, soffits, or damaged shingles. Once inside, they chew wood, insulation, and even wiring. Homeowners often first hear them as early morning scurrying above the ceiling.
Raccoons
Raccoons are powerful and persistent. They can pry open weakened vents or tear through soffits to create den sites, especially in urban and suburban neighbourhoods. Beyond structural damage, their droppings pose health risks if left unaddressed.
Bats
Little brown bats can roost in attics or wall cavities, entering through surprisingly small gaps. Because bats are protected in many regions and require specialized handling, removal must be done carefully and legally.
If you suspect wildlife activity, avoid immediately sealing openings. Trapping animals inside can worsen damage and create ethical and legal complications. Professional inspection ensures proper exclusion timing, humane removal strategies, and reinforced barriers to prevent re-entry.
Winter pests are looking for survival. A proactive plan ensures your home is not the easiest option. Learn more about why pests are getting inside your home or business.
Keep Your Property Well-Protected During Winter
Despite you and your family spending more time indoors, winter in Ontario can also bring many outdoor pests inside your home or business, where they are likely to cause more damage. The good news is, they can be prevented and/or removed with the right residential and commercial pest control in Toronto.
ABOUT THE AUTHOR
You must be logged in to post a comment.