January and February
What to expect: Mice and rats are living inside and are most active in the coldest weeks. Cockroaches, silverfish and bed bugs stay active indoors. On warm, sunny days, boxelder bugs, stink bugs and lady beetles that spent winter in your walls come out into your rooms.
What to do: Listen for scratching in walls and the attic, and check the basement and garage for droppings. Run a dehumidifier in damp basements to slow silverfish. Frequent freeze/thaw cycles can widen small exterior gaps, so note any openings to seal when conditions allow.
Related pages: Mouse Control | Rat Control | Silverfish Control
March
What to expect: Rodents are still active. Insects that spent winter in your walls start to leave. Adult ticks can appear on mild days when the ground is not frozen.
What to do: This is a good time to book a termite inspection before swarm season begins. Clean out gutters and check the foundation for cracks.
Related pages: Termite Inspection | Rodent Control
April
What to expect: Termites can swarm after warm rain. Ants and carpenter ants wake up as the ground warms. Spiders become more visible, carpenter bees start drilling into wood and earwigs begin to appear. The typical last frost comes in late April, but pest activity can start earlier during warm spells.
What to do: Look for mud tubes on the foundation, shed wings near windows and sawdust piles. Check decks, eaves and trim for round holes.
Related pages: Termite Control | Ant Control | Carpenter Ant Control | Carpenter Bee Control
May
What to expect: Termite swarms can continue. Ants are active in kitchens and yards. Queen paper wasps start small nests under eaves and on porches. Mosquitoes begin to build and tick nymphs start to appear.
What to do: Check eaves, porch ceilings and sheds every week or two for small nests. Dump standing water. This is the ideal month to start yard treatments for mosquitoes and ticks.
Related pages: Wasp and Hornet Nest Removal | Mosquito Control | Tick Control
June
What to expect: Mosquitoes and ticks are active outdoors. Wasp nests are growing. Fleas increase, ants are busy and earwigs move in around damp areas. May through July is usually the wettest period, which keeps standing water and damp shelter available.
What to do: Check pets for fleas and ticks. Empty water from planters, buckets and birdbaths weekly. Keep outdoor food and drinks covered.
Related pages: Flea Control | Earwig Control | Mosquito Control
July
What to expect: Wasps, hornets and mosquitoes are at high levels. Ticks, fleas, spiders and ants are all active. Bald faced hornet nests in shrubs and trees are growing. Regional summer humidity often averages about 65–75%, helping shaded resting areas stay damp.
What to do: Watch for nests in bushes, sheds and under decks. Keep trash cans closed and trim plants that touch the house.
Related pages: Wasp and Hornet Nest Removal | Spider Control
August
What to expect: Yellow jacket and wasp colonies reach their largest size. Mosquitoes remain heavy. Spiders are easier to see as they mature.
What to do: This is the best month to plan for the fall bug invasion. An exterior treatment now, before boxelder bugs, stink bugs and lady beetles gather, works better than one after they are inside. Also look for yellow jacket entrances in the ground and along walls.
Related pages: Yellow Jacket Control | Boxelder Bug Control | Stink Bug Control
September
What to expect: Yellow jackets are at their most aggressive. Boxelder bugs, stink bugs and lady beetles begin to gather on sunny walls. Mice start looking for shelter. Wolf spiders move toward homes. Mosquitoes continue until frost.
What to do: Seal gaps around windows, doors, siding, vents and utility lines. Keep trash and sweet drinks covered outdoors. Begin checking for signs of rodents.
Related pages: Asian Lady Beetle Control | Yellow Jacket Control | Rodent Control
October
What to expect: Mice and rats move inside as temperatures fall. Boxelder bugs, stink bugs and lady beetles cover sunny walls on warm afternoons. Adult blacklegged ticks are active. The first frost usually arrives in mid-to-late October, though mild days can keep some pests active.
What to do: Seal entry points, replace worn door sweeps and check the garage and basement. Vacuum bugs that get inside instead of crushing them. Do a tick check after time outdoors.
Related pages: Mouse Control | Rat Control | Tick Control
November
What to expect: Rodent activity rises. Cockroaches and silverfish are active indoors. Adult ticks can still be found on mild days.
What to do: Store firewood away from the house, check for droppings in cupboards, the garage and the basement, and keep food in sealed containers.
Related pages: Rodent Control | Cockroach Control
December
What to expect: Rodents and overwintering insects stay hidden inside your walls and attic. Holiday travel and guests can bring bed bugs into the home.
What to do: Check luggage and clothes after trips. Listen for noises in walls and the attic. Keep food sealed and take out the trash regularly.
Related pages: Bed Bug Treatment | Mouse Control
The Best Time to Treat Each Pest
- Termite inspection: Late winter or early spring, before swarm season
- Fall invaders (boxelder bugs, stink bugs, lady beetles): August to early September
- Rodents: Early fall, before they move in, though any time signs appear
- Mosquitoes and ticks in the yard: Start in late spring and continue through the warm months
- Wasp nests: As soon as you see one. Small spring nests are the easiest to remove
- All year protection: A Home Pest Protection Plan covers every season
Frequently Asked Questions
What is the worst month for pests in Downers Grove?
It depends on the pest. Spring brings termites and ants, summer brings wasps, mosquitoes and ticks, and fall brings mice and invading bugs. Late summer through fall is often the busiest time for calls.
When do termites swarm in Downers Grove?
Termites usually swarm in April and May, often after warm rain. If you see winged insects or shed wings inside your home, call for an inspection.
When do mice come into the house?
Mice move indoors when temperatures start to drop, usually in fall. Activity stays high through winter. Sealing gaps in early fall is the best way to get ahead of them.
Do pests go away in winter?
Many outdoor pests slow down or die off, but others move indoors. Mice, rats, cockroaches, silverfish and bed bugs can be active in winter, and bugs hiding in your walls can come out on warm days.
When should I start pest control?
Early spring is a good time to start, since you can get ahead of ants, termites and stinging insects. But if you have a problem now, do not wait for a better month.
When should I treat my yard for mosquitoes and ticks?
Late spring is ideal, before numbers build. You can still start later in the season and see a difference.
Why do pests come back every year?
Many pests follow the same seasonal cycle, and the conditions that attract them, like gaps, moisture and food sources, are often still there. Regular checks and exterior treatments help break the cycle.