Las Vegas Pest Calendar: What Shows Up Each Month

What does a pest year look like in the Las Vegas Valley?

The valley has a hot desert climate with a short, wet-ish window in the middle of summer and a cool, dry winter. Pests follow that rhythm: scorpions and ants chase the heat, mosquitoes chase the monsoon, and rodents and roaches chase warmth indoors once nights chill in the cooler months.

Las Vegas gets only about 4.13 inches of rain a year at the airport, so water, not food, is often what limits a pest. That is why irrigated yards, pool edges, drip lines and the monsoon matter so much on this calendar. A pest that is rare on open desert can be common on a watered block-wall lot.

Temperature does the rest. July averages a high near 106°F and August near 103°F, while December and January lows average near 37°F and February lows sit near 41°F. Frost shows up on several nights a year, and snow only every five years or so. That swing between a 100-degree summer and a frosty winter is the reason one calendar can hold both a peak-scorpion month and a rodents-moving-indoors month.

A word on how to read what follows. The monsoon dates, the temperature averages, the bark scorpion seasons and the termite swarm timing come from published sources. Month-level timing for other pests, like wasps, ants and Aedes mosquitoes, is general trade knowledge, so the table says things like usually, from about and in most years rather than naming a single month.

Month by month: what usually shows up and what to do

Use this table as a reference you come back to. Each row pairs the typical weather with the pests that most often cause calls that month, then one practical task. Rows built on published data are stated plainly; rows built on general experience use words like usually and from about.

The table covers the whole valley, from Henderson to North Las Vegas. Microclimates shift it a little: homes at the desert edge in places like Southern Highlands or Aliante often see scorpions earlier than a dense central block, and a lakeside or wash-side yard may see mosquitoes sooner.

If a month shows several pests, they do not all peak on the same day. Think of each row as the set of things worth a look that month, not a forecast.

What happens from December through February?

Winter is the indoor season. Bark scorpions are inactive in the cold, so outdoor sightings drop, while rodents and German cockroaches work inside walls, attics and kitchens. With lows near 37°F and several frost days a year, winter is also a practical time to inspect and seal.

Roof rats and house mice do not hibernate. When nights chill, they look for warm, dry, sheltered spots, and a Las Vegas attic or garage fits that description. Signs in this season are droppings along baseboards, gnawed stored food and scratching in a ceiling at night. Our roof rat control page covers how technicians trap and then close the roofline gaps behind them.

German cockroaches are an apartment, restaurant and kitchen pest. They live where it is warm and humid the whole year, so the calendar barely changes for them. Dense, older buildings in Winchester or along the Strip corridor tend to see steady calls from December to December.

Winter has one more advantage. A technician working in cool weather can see gaps, cracked caulk and worn door sweeps without fighting the heat, and sealing done in February is already in place when scorpion sightings start climbing in spring. That is the logic behind most scorpion exclusion work being planned in the cool months.

Which pests wake up between March and May?

Spring brings the first warm days, and the first complaints. Bark scorpion sightings begin climbing, ants follow irrigation lines, a spring termite swarm is possible, and Aedes mosquitoes usually start ramping up. Wasps and bees tend to build nests as heat arrives in May.

Published scorpion guidance describes sightings rising from spring through early fall, with spring and autumn both acting as mating seasons. If you saw nothing all winter, a scorpion on a wall in April does not mean a new infestation. It often means the colony in a hollow block wall has simply warmed up. See the scorpion control page for how that is handled.

Ants are tied to water in a dry climate. Drip irrigation, pool plumbing and sprinkler boxes give them moisture, and ant trails in a kitchen in April often trace back to a leaking irrigation valve outside. Termites can also swarm in spring, but the valley's main swarm window is autumn, which the termite guide on this site explains in detail.

April and May are when yard habits matter. A saucer under a potted palm, a bucket left under a hose bib or a pet bowl on the patio can hold enough water for container-breeding mosquitoes. Emptying and scrubbing them weekly costs nothing and is the first step of mosquito control.

What peaks from June through August?

Summer is the peak for bark scorpions and a busy time for mosquitoes, wasps and Turkestan roaches. July highs near 106°F push insects toward water and shade, and the monsoon, which typically starts in early July, adds standing water and humidity that bring a second wave of calls.

Bark scorpions are at their peak in summer. They shelter in hollow concrete block walls, reaching the voids through narrow cracks, and come out at night to hunt. A blacklight shows them clearly because scorpions fluoresce under UV light, which is why technicians and homeowners both use one after dark.

Turkestan cockroaches live mostly outdoors and move inside during the hot months. If large, dark roaches appear near a back door or in a garage in June, that is typical behavior, not a sign of dirty housekeeping. Heat and a dry yard are what drive them toward cooler, damper spaces. A Clark County report also linked one east-valley roach outbreak to nearby construction disturbing soil, plus rain and heat, which is a reminder that disturbed ground matters.

Mosquito testing ramps up in June, and the Southern Nevada Health District runs surveillance across the season. West Nile virus has been detected in Aedes aegypti in Clark County, so standing water in July and August deserves attention. Our mosquito control page covers what a service visit looks like.

Mid-summer is also when many calls come from a stinging insect rather than a crawling one. Wasps and bees tend to occupy eaves, tile-roof gaps and palm fronds through the long warm season, so look at the roofline before a family gathering on the patio.

What changes in September, October and November?

Autumn is a handoff. Scorpions are among their most active in September, then go inactive as nights chill in November. The monsoon ends around mid-September, termite swarms can run through October after the first autumn rains, and rodents begin moving indoors as nights cool.

September is a month people do not expect to be busy. The monsoon has left moisture and the heat is still strong, so scorpion sightings can be among the highest of the year. Walking a wall with a UV flashlight after dark in September is a good way to learn where scorpions are actually entering.

The termite swarm is the signature autumn event. Swarms are linked to calm, sunny days after the first autumn rains, and reports run into October. A swarm indoors usually means a colony is nearby, because swarmers are the reproductive termites leaving an established colony. The termite control page explains what happens next.

Rodents start looking for shelter in October and November. Fruit that falls under citrus, dates left on palms and pet food kept outside all draw roof rats, which climb palms and block-wall tops to reach attics. Trimming fronds and removing fruit in October is cheaper than trapping in January.

How do I use this calendar to plan the year?

Pair each season with one job. Seal and inspect in winter, screen and sweep in early spring, drain water before the monsoon, use a UV flashlight in September, and check for swarmers in October. Calling a technician at the first sign of a problem is cheaper than waiting for peak season.

A calendar is most useful when you turn it into a short list you actually do. These are the jobs most valley homeowners can tackle themselves, in the order the seasons call for them. For anything that involves entry into a block wall, a roof or an attic, it is safer to call a technician than to climb or probe yourself.

If you want a technician to look at a specific problem, phones are answered 24/7 at (855) 974-4733, and same-day visits are scheduled when a technician is free. You approve the price before any treatment begins.

• January to February: inspect attics, garages and under-sink gaps; plan any sealing work for the cool months.
• March to April: replace door sweeps and torn window screens, and scrub every container that can hold water.
• May to June: look at block-wall caps, weep screeds and tile-roof eave gaps before scorpion and wasp season.
• July to August: after each storm, walk the yard and dump standing water within a day or two.
• September: do a UV flashlight walk along walls, door thresholds and patio edges after dark.
• October: watch window sills for shed wings and keep fruit and pet food off the ground.
• November to December: trim palm fronds and fruit-tree limbs away from the roofline and check kitchens for roach activity.

What does a seasonal plan cost?

Seasonal pest plans are usually priced per visit, and a typical range depends on the pest. A published national guide puts quarterly general service at about $90 to $300 per visit, while one Las Vegas company advertises single general visits starting around $72. These are estimates, and the price is confirmed on site.

Scorpion work shows how much the pest matters. Local company quotes and national guides put a one-time scorpion service at about $135 to $300, and monthly scorpion service at about $35 to $80. Sealing a home against scorpions as a one-time project has been estimated at $400 to $1,500, depending on the size of the home and the number of gaps.

Mosquito service during the season has been estimated at about $50 to $150 a month, and one local company starts at $149 for a service. All of these figures are typical estimates drawn from local company pages and national guides, not quotes from Las Vegas Pest Control. Your technician confirms the exact price on site before any work begins. For a deeper breakdown, see the pest control cost guide.