How does weather effect bugs?

In all of my years as a pest control technician, one of the most asked questions customers give me is, “Don’t bugs slowdown in bad weather?” I can understand why most people assume that bugs slow production in bad weather because we as humans slow up quite a bit. The truth though is most bugs thrive in the rain, dry weather, and even snow. In this article, I will address some major bug invasions that center around the weather and how it can effect PCM (pest control management).



A great deal of bugs love the rain. Centipedes, Millipedes, and Sow Bugs love a wet environment. Centipedes and Millipedes are often referred to as “lady screamers” or “thousand leggers” by many people. Sow Bugs are usually referred to as “pill bugs” or “rolly pollies”. When outside these three bugs can be found under rocks and damp areas. When the weather has been wet for a while they will breed and love to hang out in the wetness. Problems arise for individuals when the weather dries up and stops raining for a few weeks. Because these pests love the dampness, they will seek shelter inside homes. Typically homes with basements or crawl spaces are the most impacted by their invasion. They will live in these areas and reproduce once inside. After they reach a substantial number they will seek ways to get into the living space of the home. Because they love the wet environment, millipedes, sow bugs, and centipedes are commonly found in bathrooms and kitchens.

Another insect that tends to invade after a good rain storm are ants. Ants work all the time, keeping stored food and taking care of reproductives. Ants will typically store 6 months of food inside their nest. What happens when it rains is the ants are not able to forage for food. This will entice them to dig into their stores. Once the rain has lifted, these little insects will seek food wherever they can get it. Inside your home often proves to have abundant opportunity for the ants to replenish their supplies. In fact, a great deal of my customers will never complain of ants being among their pest nuisances in the home, but let it rain and they tend to get a few shortly after a storm. Once ants get inside a home and are able to find a good source of food or water, they will move their nest or set up a satellite colony inside the residence. This allows them to forage for food in a more convenient location. We have a nice Ant FAQ here for more information.

The wet weather can also provide a place for mosquitoes to breed. See our article on mosquitoes and the diseases they carry here for more information.

Dry Weather / Hot weather

Other than the bugs mentioned above, a great deal many of critters will seek refuge inside your home in extreme heat or dry weather. Just as humans love to come inside a nice cool house during the summer, bugs and rodents enjoy the refuge from the heat as well.


Mice and rats tend to invade all year. They do not like changes in the weather or extreme temperature changes. In the summer, the heat will drive rodents into the home. Normally in the summer, lack of rain and cool days will cause mice to seek harborage inside your house. Grass will stop going to seed in a drought and this can cause food to become scarce. Likewise in the winter when the grass and other food sources die back, mice will try to enter the home to feed.

“But I thought mice were the worst in the spring and fall?” people will ask me. That is right. Mice and rats alike both typically will try to enter the home in greater numbers in the late fall and early spring months. This is due to the rapid change in temperature at night time. The cold nights will cause mice to try to get inside for a warm place to sleep. In the wild they will find harborage in hollow trees, old stumps or borrow around tree roots to stay warm. If your home is not properly sealed (and sometimes even if it is) they will feel the warm draft and try to get inside. A mouse only needs a hole a little smaller than a dime to fit through to enter your home. Check out our “Are Mice Dangerous” article for a more in-depth view of these critters.

Fleas and Flies


After a few months into the warm weather, a great deal of people with AND without pets will begin to see fleas. Usually the worst time for fleas is arid weather. The heat helps to hatch the eggs and the movement of deer, mice, squirrels, and groundhogs will bring these blood suckers into your yard. Usually the most common customer that calls me does have pets and these are the primary carriers of fleas into the home but it is very possible to get a flea infestation without ever owning a pet at all.

As animals travel through your yard, they will lay down, feed, and scratch themselves. This will cause flea eggs to fall off of their fur and then all you have to do is walk by. They hatch out of their cocoons, jump towards you, and hitch a ride inside the cool house where they will feed on you, and infest the home.

We offer indoor treatments that are safe for your family and pets. Also, with a proper yard treatment, flea problems can be helped a great deal. Ask us about treating the yard when you call. For more information of fleas we have an article titled “How can I get rid of Fleas?” here.



A common pest that people get inside the home during warm weather are fruit flies. Berries, apples, grapes, and other types of fruit is brought inside the home in the warm months. When on store shelves or even before it is picked, fruit flies will lay their eggs on fruit. You cannot see the eggs and bring the food into your home. Once inside the eggs will hatch and usually within a couple days you will begin to see fruit flies. These can be extremely annoying and once inside will breed in trash cans, bathrooms, and drains. There are DIY fruit fly traps that are extremely effective in capturing these creatures and if you ask us when you call we can explain one of the best that we have made over the years that costs pennies to make yourself.

Winter Weather

“I sure hope we get a nice cold winter this year so some of these bugs will die off.” This comment right here is the most popular statement among my customers. While the cold will slow up the reproduction of most if not all bugs this statement is nearly 100% untrue.

Bugs hibernate in the winter. Ants will go deep underground or into a hollow tree where they can stay warm. They will also try to find places inside the walls of your home to survive winters.

spiderSpiders can almost freeze solid, then thaw and survive cold winters. This is why you can find spiders spinning webs as early as January here in Virginia.

Cluster flies will invade the house during the early winter when it is still slightly warm. These, along with stink bugs and lady bugs slow up so much in the winter they will appear to be dead but if you warm them up, they will come to life and begin to fly around again.

Most breeds of cockroaches, if they can’t make it to a warm place, will die if they get too cold. Their eggs, however, can survive extreme temperature changes and are unaffected by the cold.

The truth about the winter is, if bugs died off, eventually we would stop having bugs all together. Once the weather is warm again, bugs can be seen foraging and reproducing with the motivation to preserve their kind. This is because they can survive the winters better than most of us!

So remember, just because the weather isn’t the best for us humans. There are always a few pests out there that can’t wait for the drip drops of a cloud burst to come out and play. Cold weather is just another cycle that all bugs are fine tuned to survive.