Why Do Mice Come Into The House In The Summer? (Simple)

A mouse coming into a house in the summer

Figuring out why mice come into the house during summer isn’t as hard as it seems. In fact, the reasons are all rather obvious!

This guide will help you understand why mice are ending up in your home during the warm months, and teach you what to do about it.

Why Do Mice Come In The House In The Summer?

Having mice come into your house during the summer months may surprise you, but this occurrence is actually very common. As long as your home provides the essential things they need, mice will come in, no matter the season.

Here’s a list of common reasons why mice might be in your house during the summer.

1. It’s Hot Outside

Just like you, mice will do almost anything to get out of the scorching summer heat. Your home (especially if you have air conditioning) will seem like a paradise for any mouse seeking to escape the heat and sunshine.

Once the mice get in, they will usually seek out the coolest places in the house such as a basement, cellar, or a crawl space.

2. They Were Already In Your Home

If you’ve seen evidence of a mouse in your home during the summer, it doesn’t necessarily mean that the mouse is a recent visitor. It’s actually more likely that you have had mice in your house for longer than you have realized.

Mice love the warmth and shelter that your attic can provide during the long, winter months. However, once the summer rolls around that once comfortable attic can quickly become an inferno. In general, mice will seek out other areas of your home that are cooler than the attic.

This usually means that mice who were already in your home will seek out the cool temperatures of a basement, cellar, or crawl space. Not only will they go into these cooler spots during summer, but they will often abandon their old attic nests and build new ones in the basement.

3. They Want To Get Dry

While mice will seek places where there is an available water supply, they don’t really like to get wet. Those wonderful summer downpours that nourish your garden and keep your lawn healthy, will tend to drive mice into places where they can keep from getting soaked.

Unfortunately, that often leads to mice coming into your house during the summer.

Expert Tip: Interestingly enough, if you have a basement that stays moist or has standing water after lots of rain, that water will actually attract mice to the area. Mice love it where it’s moist, not where they will get wet. That’s why it’s important to keep your basement as free of moisture as you can. 

4. It’s Easily Accessible

Any and all of the above reasons could be why you have mice in your house during the summer. However, if it’s easy for these critters to enter your home, then it doesn’t matter what time of the year it is.

You will have mice.

These pests can get into just about any gaps, cracks, or holes in your house, so it’s worth it to take a look around and plug up any entry points that you might see. It’s extra important to do a house inspection after the winter is over, because the cold and ice can make holes that were tiny in the autumn, become bigger by the end of the winter. 

If you have mice in your house during the summer, it’s important to address the problem quickly. Seeing one mouse usually means that there are lots of others hiding out, acting now will save you work later!

Will They Leave When The Season Changes?

Many people who find that they have mice in their house in the summer mistakenly think that if they just wait it out, these pests will leave once the cooler weather hits. While this is sometimes the case, the mice are usually there to stay.

Most likely, mice are in your home because they are taking advantage of the food, water and shelter that your house provides. As long as the mice have everything they need, they have no reason to leave. They might switch their basecamp once the weather changes, but they are not likely to leave your house just because summer ends.

However, there are some things that may cause mice to seek shelter elsewhere. Cats, dogs, and other pets are often a reason that mice will vacate a home. Eventually though, the mice can come up with ways to outsmart them.

Expert Tip: An exception to this is if you own a cat that is a very good hunter. In this case, mice are more likely to become discouraged and leave.

Some people try keeping their home very cold in the winter to discourage mice from hanging out in your home. This is not a sure fire way to get rid of mice, so it’s best not to depend on this method.

It’s important to remember that mice are basically nocturnal, so if you don’t actually see mice around, it doesn’t mean that they are gone. Keep your eyes open for droppings, gnaw marks and eaten pantry items. The tell-tale smell of mouse urine is another sign that the mice in your home have not left at the end of summer.

What About Mice In Your Basement During The Summer?

If you have mice coming into your house during the summer, chances are that they are going to settle in your basement at some point. During the heat of the summer months, a basement is often one of the coolest places in a home. Since one of the reasons a mouse will come into your home during the summer is to get out of the heat, it makes sense that they would seek out the coolness of a basement.

Another reason that mice will invade a basement during the summer is that many basements are places where mice can find some kind of moisture. Lots of basements have moist, often dripping walls, so mice are able to get all the water they need. Summer rain storms can cause flooding in a basement, and this is another source of water that many mice find irresistible. 

How will you know if you have mice in the basement? The easiest way is to actually see one. Another obvious sign is if you notice a foul, unpleasant odor in your basement. This could be from urine or mouse droppings (or even a dead mouse). This is another sure sign that mice have been in your basement.

Have you noticed gnaw marks on things such as wood or boxes? Hearing odd scratching or scurrying noises? These are very good signs that mice have been in your basement. 

If you suspect that you have mice in your basement while it’s summer, it’s important to have a pest control professional evaluate the situation or handle things yourself (if you’re comfortable). Mice are carriers of a variety of diseases, and they will chew everything in sight, including electrical wiring. 

How To Deal With Mice In The House In Summer

Discovering mice in their house during the summer is something that many people experience each year. They come in for food, water and shelter from the heat, or they are already there from the winter and decide to hang around. No matter the reason, it’s very important to get rid of them and keep them out. There are several ways to do this, and how you do it kind of depends on the situation.

So what are some things that you can do? Most of the methods we will discuss are common sense, inexpensive, and fairly easy to do.

Let’s take a quick look at some of our favorites.

Check For Entry Points

As we mentioned above, a good first measure is to try to prevent mice from entering your home at all. Take some time to carefully examine the outside of your home for holes, cracks and gaps.

Mice are able to fit into pretty small spaces, so don’t overlook anything that you assume is too small. In fact, the average mouse is able to fit into a hole or crack that is the same size as the width of a pencil. Fill in these cracks and keep your eyes open for new ones.

Clean Up The Yard

If you want to stop finding mice in your house during the summer, keeping them off of your property will go a long way. If nothing in your yard is attracting them, your house won’t even be a consideration.

Make sure that your yard is free of all debris, clear out old wood piles and keep the grass cut short. All trash cans and recycling bins should be tightly covered. Keep family areas, like decks and patios, free of food, beverage spills and trash. If you feed your pets outside, keep this area clean as well. 

Cut back any tree branches that are hanging close to your house. Mice are great climbers and can actually use the branches to get onto your roof.

Don’t Forget The Inside

After you’ve taken care of the outside of your home, you will need to take a look around the inside. If you want to get rid of the mice that enter your home in the summer, you’ll need to eliminate whatever attracted them in the first place.

So what are some of our recommendations? The first thing is to keep your kitchen and living space as crumb-free and clean as possible. This means that all dishes should be done at night, countertops and sinks should be wiped down, and floors should be swept and vacuumed. If possible, try to avoid eating and drinking in non-dining areas.

Keep all pantry items and pet food in tightly sealed, heavy-duty plastic containers, take out the trash every day and keep pet-feeding areas clean and swept.

Just like you looked around the outside for holes and cracks, you should do the same thing inside your home and fill up anything you find (steel wool can help with this). It’s also important to check for any type of plumbing leak whether inside or outside of your home. Mice love moisture, and even the slightest hint of moisture or dripping water could be the perfect incentive for them to stay. 

Place Traps And Repellents

The last thing to try is to set traps, put down bait or try one of the many ultrasonic pest repellents on the market (but be mindful if you have dogs).

Many people even use cotton balls soaked in natural oils such as peppermint, cayenne and clove. These are then placed in areas that are known to be prone to mice.


There are a number of reasons why mice will come into your house in the summer. Fortunately, once you know these reasons it becomes easy to take care of these pesky critters!

If you’re having some trouble and need more advice, send us a message through our contact page. We’ll gladly give you a hand.

Previous Post
Antifreeze that can be used for killing groundhogs

Killing Groundhogs With Antifreeze: How To Do It

Next Post
A computer with mites in it

How To Get Rid Of Computer Mites: A Simple Guide