Pest activity in St. George follows the Mojave calendar: long, very hot summers, a monsoon season in late summer, and mild winters that slow pests down without stopping them. That rhythm is predictable enough to plan around.
Here is what each part of the year tends to bring across Washington County, and what is worth doing before each season starts.
Winter: December Through February
Winter here is the slow season, not the off season. Cooler nights push rodents and spiders toward houses, and warm afternoons keep plenty of insects moving.
What you will see:
- Mice and pack rats looking for shelter in garages, attics, and engine bays
- Spiders, including black widows, staying active in garages and block walls
- Occasional ant activity on warm days
- Cockroaches around plumbing, water heaters, and sewer lines
What to do:
- Check the attic, garage, and storage areas for droppings and nesting material
- Seal gaps around pipes, vents, tile roof edges, and garage doors
- Store food, pet food, and birdseed in sealed containers
- Clean out cluttered garages and sheds to remove hiding places
- Fix any leaks now, before warm weather speeds everything up
Spring: March Through May
This is when the year really starts. Warming soil, blooming landscaping, and irrigation systems running at full tilt bring a fast rise in insect activity.
What you will see:
- Ant trails along foundations, sidewalks, and kitchen counters
- Harvester ant mounds appearing in yards and gravel areas
- Paper wasp and yellowjacket queens starting new nests under eaves and patio covers
- Scorpions becoming active as nights warm up
- More spiders as their prey returns
What to do:
- Follow early ant trails back to where they enter instead of spraying what you see
- Check eaves, patio covers, and play structures for small, new wasp nests
- Pull rock, leaves, and debris back from the foundation
- Inspect door sweeps and window screens
- Start a treatment plan before colonies settle in; spring is the most effective time of year to get ahead
Summer: June Through August
The heat is the story. When afternoons hit 105 degrees or more, pests go looking for shade and water, and in the desert the most reliable sources are irrigated yards and the inside of your house.
What you will see:
- Scorpions moving up walls and slipping indoors on hot nights
- Paper wasp and yellowjacket nests at their largest and most defensive
- Ants concentrated around sprinkler lines, drip emitters, and any indoor water
- Crickets, cockroaches, and earwigs around damp areas
- Mosquitoes near the Virgin River, washes, and standing water once monsoon storms arrive
What to do:
- Aim sprinklers and drip lines away from the foundation and walls
- Fix irrigation leaks quickly; a leaking line in July draws pests from all over the yard
- Dump standing water after monsoon storms to cut down on mosquitoes
- Leave established wasp nests to a professional, especially later in the summer
- Switch outdoor lights to warm-toned bulbs, which attract fewer insects at night
Fall: September Through November
As temperatures finally ease, pests that spent the summer outdoors start looking for a place to settle in for the cooler months.
What you will see:
- Mice and other rodents probing for entry as nights cool
- Spiders moving inside as outdoor prey declines
- Millipedes and crickets after late monsoon rains
- Wasps becoming more erratic as colonies wind down
- Continued scorpion activity on warm evenings
What to do:
- Finish sealing and exclusion work *before* the cooler nights set in; this is the most important prevention window of the year
- Close up entry points at the roofline, foundation, and utility lines
- Replace worn door sweeps and weatherstripping
- Trim branches and shrubs back from the roof and walls
- Clear debris from rain gutters and roof valleys
- Keep firewood stacked off the ground and away from the house
What Ties It Together
Each season's pest problem is set up by the one before it. Spring ant colonies grew from fall foraging. Winter mice came in through gaps that were open in October. A summer wasp nest started with one queen in April.
That is the case for ongoing service instead of one-off treatments. Regular visits handle each season's setup before it turns into the next season's infestation, and they catch problems while they are small and inexpensive to fix.
If you would like to stop reacting to whatever shows up next, contact Butter Pest Control. We will put together a plan based on what your property actually faces through the southern Utah year.
Dealing with this pest at your place?
Butter serves St. George and southern Utah with free inspections and a re-treatment guarantee. Get an honest quote, no pressure.
Aspen Chournos
Aspen Chournos writes about desert pest pressure and prevention for homes and businesses across St. George and southern Utah.
