We’re still in the heart of rainy season, and it’s looking like rain is going to continue over the course of the next several weeks. But the weather is also getting warmer as we get deeper into spring, which is typically when pest start to become much, much more active.

If it’s raining, but it’s also spring, what is the rain going to do to pests? Are they going to become more common? Less? What do they do in the rain anyway?

Let’s examine what pests do in the rain and how it might affect pest control.

How Rain Affects Common Pest Behavior

Different types of pests respond to rain in various ways depending on their species, habitat, and biological needs. Most pest behavior during rain falls into one of three categories: seeking shelter, increased activity, or emerging to feed or reproduce.

Seeking Shelter

Pest like water, but not *while* it’s raining. Many pests seek dry, protected areas when it rains to avoid drowning or exposure to cold and wet conditions. Homes, garages, and sheds often become prime targets for pests looking to escape heavy rainfall.

• Ants – When rain floods underground ant colonies, worker ants relocate the colony to higher ground or indoors. This often results in sudden indoor ant infestations after heavy rainfall.
• Cockroaches – Roaches are highly sensitive to moisture changes. When rainwater displaces them from sewers and drains, they often enter homes through cracks, vents, and plumbing systems to find dry shelter.
• Rodents – Mice and rats seek dry, warm environments when their nests become waterlogged. They are known to squeeze through small openings in foundations, gaps in walls, or around pipes to avoid drowning or exposure.
• Spiders – Spiders prefer dry environments. Heavy rain drives them indoors, where they often seek refuge in dark corners, basements, and crawl spaces.
• Earwigs and Centipedes – These moisture-loving pests seek dry shelter when heavy rain becomes excessive, often showing up in bathrooms, basements, and under sinks.

Pests entering homes during rainfall often become more difficult to control because they exploit small openings and hard-to-reach hiding spots.

Increased Activity

While some pests seek shelter, others become more active when it rains due to changes in humidity, soil saturation, and food availability. For example:

• Mosquitoes – Rain creates standing water, which serves as a breeding ground for mosquitoes. After rainfall, mosquito activity often increases as they take advantage of new breeding sites, although during rainfall they may be less active.
• Termites – Termites are drawn to moisture. Damp wood created by rain provides an ideal environment for termites to tunnel and feed, increasing the risk of structural damage.
• Earthworms – Earthworms surface during rain because saturated soil reduces oxygen levels underground. This behavior often attracts predators like birds, which can further disrupt the environment.
• Slugs and Snails – These moisture-loving pests are more active during rainy weather, feeding on plants and vegetation. Increased rain can lead to more noticeable garden damage from these pests.
• Springtails – Springtails thrive in moist environments. Rain encourages them to gather near foundation walls and windows, where they may enter homes if moisture levels remain high.

Increased pest activity during rain often leads to population surges, making it harder to control infestations after the rain subside, although most pests will typically wait for the rain to stop before they’ll be this active.

Emerging to Feed or Reproduce

Certain pests take advantage of rainy weather to feed or lay eggs, using the increased moisture to support their life cycle.

• Mosquitoes – Female mosquitoes lay eggs in standing water left by rain. Larvae can hatch within 24 to 48 hours, leading to rapid population increases.
• Fleas and Ticks – Wet weather increases vegetation growth, providing more coverage for fleas and ticks. Increased humidity also helps support flea and tick reproduction cycles.
• Gnats and Midges – These flying insects thrive in wet, humid conditions. Rain increases their breeding activity in damp soil and standing water.

Emerging pests not only increase in number after rain but also become more aggressive in seeking out food sources and new nesting areas.

Why Rain Draws Pests Toward Homes

Pests are drawn toward human structures during and after rain for several key reasons:

• Moisture – Increased humidity and waterlogged soil drive pests toward drier, more stable environments.
• Food Sources – Rain can wash away food sources in natural environments, leading pests to seek alternative sources inside homes.
• Shelter from Predators – Pests become more vulnerable to birds, amphibians, and other predators when displaced by rain, driving them toward human structures for protection.
• Structural Weaknesses – Rain can soften wood, increase gaps around doors and windows, and create water damage that opens new entry points for pests.

These issues can affect pests not only when the rain stops, but also while it’s raining, increasing the odds of a problem that may affect homeowners.

How to Minimize Pest Activity During Rain

Since pests are more likely to enter homes during rainy weather, homeowners can take steps to reduce the likelihood of an infestation:

• Seal Entry Points – Close gaps around windows, doors, and foundation walls to prevent pests from entering during rain.
• Improve Drainage – Keep gutters clean and direct downspouts away from the foundation to prevent water buildup and standing water.
• Remove Standing Water – After rain, empty containers, plant trays, and other objects that collect water to prevent mosquito breeding.
• Trim Vegetation – Keep shrubs and trees trimmed away from the house to reduce pest access points and hiding places.
• Use Dehumidifiers and Ventilation – Reducing indoor humidity makes the environment less attractive to moisture-seeking pests like roaches, ants, and silverfish.

You’ll also want to make sure that you have pest control – professional pest control – that was designed for a rainy season. Many of the pest control tools available retail are not designed for rain, and may not be able to keep the pests out. At ExtermPRO, our pest control solutions are designed for rain, so they’re built to last even when it’s rainy and windy.

Managing Pests During and After Rain

Rain significantly changes pest behavior, increasing the likelihood of infestations and structural damage. Perhaps even more troubling is that after the rain is over, pests have everything they need to thrive, breed, and spread. If you’re looking for help with your pest control and want someone you can trust during rainy seasons, reach out to ExtermPRO today.