​Monsoon season gets a lot of attention in Arizona, especially when it comes to pests. Rain can quickly change what we're seeing around homes in Phoenix, Tucson, and throughout Southern Arizona.

But what if more rain arrives after the monsoon season is over?

That's a possibility this year. El Niño is strengthening, and NOAA says there is a greater than 90% chance it will become a very strong event during fall and winter 2026–27. Historically, El Niño can increase the chances of wetter winter weather in the Southwest.

That does not mean Phoenix, Tucson, or other Southern Arizona communities are guaranteed a rainy winter. It also doesn't mean El Niño will cause more pest problems. But if our region does receive more cool-season rain than usual, it could change when and where homeowners notice certain pests.

house after the rain

Could Phoenix and Tucson See More Rain After Monsoon Season?

Yes, and this is where El Niño is different from the summer weather most Arizona homeowners associate with rain.

Arizona's monsoon season runs from June 15 through September 30. The thunderstorms that roll through Phoenix and Tucson during that period are part of the summer monsoon.

An El Niño-influenced winter is different. If we receive additional precipitation later this fall or winter, it would generally come from cool-season weather systems rather than an extension of the summer monsoon.

That distinction matters when we're talking about pests because moisture would be arriving at a different time of year, when temperatures and pest activity are also changing.

How Could a Wetter Winter Affect Pest Activity in Phoenix and Tucson?

We've already seen how quickly rain can change pest activity during an Arizona summer. University of Arizona Cooperative Extension notes that monsoon rain can bring some pests to life while forcing others from their usual hiding places. In 2026, Extension specifically reported rain as one of the conditions associated with American cockroaches moving from sewers and into homes.

Would winter rain have exactly the same effect? Not necessarily. Temperatures are lower, and many pests are less active than they are during summer. Still, extra moisture could affect pest activity around homes in Phoenix and Tucson. Here are a few examples of what homeowners might notice.

Cockroaches and ants: Rain can disturb outdoor nesting and hiding areas, sometimes sending cockroaches and ants toward drier, protected spaces. That doesn't mean every rainy day will send pests into your kitchen, but openings around doors, plumbing, foundations, and other parts of the home can give them a way inside.

Scorpions: Scorpion activity generally slows as temperatures drop, so a wetter winter doesn't necessarily mean homeowners will see more scorpions. Rain can affect scorpion hiding places and the insects they feed on, though, which could influence where these pests are found when they are active.

Rodents: More winter rain can encourage vegetation growth and increase food available to mice and rats outdoors. That can support more rodent activity around a property, while colder or stormy weather can also send mice and rats looking for protected shelter in garages, sheds, attics, and homes.

The important point is that El Niño isn't a switch that suddenly turns pest activity on. If this winter is wetter than usual, it would simply add another factor that can influence what pests are doing around a property.

Should Phoenix and Tucson Homeowners Expect More Pests This Winter?

Phoenix and Tucson already have winter pest activity, and if El Niño brings more rain, some pest problems could become more noticeable.

That doesn’t mean every home will see more pests, but a wetter winter could change what homeowners encounter compared with a typically drier season.

Year-Round Pest Control for Phoenix and Tucson Homes

Whether we end up with an unusually wet winter or barely notice El Niño at all, pest problems don't stop when monsoon season ends.

Northwest Exterminating offers year-round home pest control and termite protection for homeowners in Phoenix, Tucson, and communities throughout Southern Arizona. Our ongoing plans are there through the changing seasons, so protecting your home doesn't depend on predicting what the weather will do next.

Regardless of what this fall and winter bring, you can rely on Northwest Exterminating to help protect your home from pests and termites all year long.

Schedule your pest control service today.