Start preventive treatments in early spring, before the ground fully thaws. Once temperatures stay above 10°C for several days, overwintering insects like ants and cluster flies begin to stir. Waiting until sightings become regular usually means you’re already behind. Pre-emptive sprays or perimeter dusting around foundations and entry points can help reduce infiltration before it escalates.
By July, wasp nests are at peak expansion. If you’ve spotted one, avoid sealing it or disturbing it. That only pushes them indoors or triggers aggression. Mid-summer is also when mice begin testing structures for warmth ahead of cooler nights. A common mistake? Sealing gaps without checking for activity first–trapped rodents can chew through insulation or die inside walls. Use monitoring stations or baited traps before exclusion work.
Come fall, field insects migrate inward. Boxelder bugs, sowbugs, and even earwigs show up in basements and around window frames. Treatments work best when applied right as temperatures dip consistently below 7°C. Delaying service until after sightings increase reduces effectiveness, since many intruders may already be inside, hiding in wall voids or attic spaces. Once they settle, it’s harder–and slower–to flush them out.
Winter doesn’t mean it’s quiet. Not in Calgary. Indoor infestations, especially with German cockroaches or stored product beetles, often become more noticeable when homes stay closed up. Dry heating systems push insects out of hiding. If you’re hearing scratching in ceilings or walls, especially at night, it’s likely mice or voles. It’s tempting to assume you’re safe when snow is on the ground, but that’s rarely the case indoors.
Common Household Pests by Season and Their Behaviors
Start by checking windows and door seals in early spring. That’s when ants–especially carpenter and pavement types–begin forming trails toward kitchens and bathrooms. They’re after moisture and easy carbs. If you notice a sudden stream near the dishwasher or under the sink, it’s probably not random. Cut off access by sealing cracks, wiping counters often, and storing food in airtight containers. Baits might help, but they work slowly.
As temperatures climb, wasps and cluster flies become more noticeable. Wasps build nests in eaves, patio roofs, even lawn furniture–sometimes almost overnight. Their behaviour turns more aggressive mid-summer, especially around sugary drinks or protein-rich food at barbecues. Removing small nests early in the day, with caution, can prevent bigger problems later. Though honestly, I’ve tried that once and regretted it–professionals have better gear and fewer regrets.
Late summer to early fall is spider season indoors. They’re not migrating in–they were there all along, but now the males are on the move looking to mate. Vacuuming regularly (especially basement corners and ceiling edges) helps. But if you’re spotting several house spiders daily, there’s likely a steady food source–usually fruit flies or fungus gnats. Cut back on moisture, check plants, and look for small water leaks.
By November, mice start exploring basements and pantries. They only need a gap the size of a dime. Watch for droppings behind the stove or shredded fabric in closets. Snap traps near baseboards still work best, placed at right angles to the wall. Peanut butter seems to outperform cheese every time. Don’t just rely on one method though–patch up entry points or they’ll be back next week.
For more visual insight on common intruders throughout the year, take a look at pinterest.com about The Pest Control Guy. You’ll find photos, tips, and some surprising examples of just how sneaky these creatures can be.
How Weather Changes Influence Pest Infestations
Start sealing gaps and cracks before spring thaws–mice often sneak indoors right after snowmelt. They’re looking for warmth, not a full buffet. That comes later, once food becomes scarce outdoors. Sudden temperature shifts tend to push insects like ants and spiders inside too, especially when outdoor humidity drops fast after a storm or cold front.
During heatwaves, expect an increase in flying insects near your home’s cooler, shaded areas. Wasps, for instance, get more aggressive when it’s hot and dry. They nest under eaves, behind shutters–basically anywhere that offers relief from direct sunlight. It’s not just discomfort; the heat speeds up their breeding cycle.
On the flip side, heavy rains often flush out ground-dwelling bugs. You’ll notice them popping up in basements, laundry rooms, or anywhere with lower elevation. They’re not lost–they’re escaping soggy nests. Cockroaches, in particular, thrive in damp indoor spots right after a prolonged wet spell.
One odd thing: a mild winter doesn’t always mean fewer problems. It can actually give many critters a better chance of surviving through to spring. Shorter freeze periods allow earlier mating, especially among rodents and some beetle species.
To keep ahead of these shifts, monitor local forecasts. Sudden barometric drops or long dry stretches often lead to increased intrusions. It’s also worth browsing resources like behance.net about The Pest Control Guy for insight on timing your prevention efforts.
There’s no perfect calendar for this. Weather patterns are unpredictable. But reacting to changes–rather than the season itself–tends to get better results long-term.
Best Timing for Scheduling Specific Pest Control Treatments
For ant problems, late spring is usually the smartest window. Colonies become more active as soil warms up, so treating just before major foraging begins can cut off trails before they reach your kitchen. Mid-May to early June tends to hit that sweet spot–at least around Calgary. Carpenter ants are more stubborn, though. If you’re hearing them in walls or seeing sawdust, don’t wait. Any time is the right time once there’s evidence inside.
Wasps are different. Don’t bother in April. The nests are too small, and you might miss them entirely. Wait until early July, when colonies are aggressive but still exposed enough to treat. Trying too late–say, September–makes access trickier, especially if they’ve settled under siding or deck boards.
For rodents, late summer into fall is usually best. That’s when they start trying to move indoors. Mid-September to October is a narrow but reliable window. If you treat before the first cold snap, you’re likely to intercept them before they nest in wall cavities or behind appliances.
As for cockroaches? Any time’s valid once you see them. But if you’re managing a multi-unit building or planning preventative work, avoid the coldest months. Gel baits and dusts don’t work as well in places where air is too dry or temperatures drop below 18°C. Spring or early fall is better for wide-area treatment.
Also, there’s a timing wrinkle for landlords or renters wondering who handles what. This depends partly on when issues show up. If they emerge right after moving in, responsibilities might shift. Check this out: Is pest control in Calgary the landlord’s or the tenant’s duty?.
One last bit–bed bugs. Don’t try to “time” that. If you spot them, act. Every week you delay makes treatment harder and longer. You won’t outwait them, and they don’t care what month it is.