Winter Fly Problems: All You Need To Know

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As winter begins to set in, so do the winter fly problems. Flies that would normally be outdoors looking for food now enter your home as they attempt to survive the cold weather. Winter flies are also known as cluster flies.

Cluster flies will hibernate in large groups on the walls or ceilings of your home. Cluster flies are larger than houseflies and can be distinguished by their yellow markings. They are not as common as houseflies, but they can be a nuisance in the wintertime.

A particular kind of fly becomes very active during the winter season. This fly is yellow or golden due to the tiny hairs on its body. They can be a nuisance when they get into your home, but there are ways to deal with them.

There are many types of flies, but this article will focus on the winter fly. Winter flies breed in soil and host on earthworms. They have a larva stage of development, which is when they are most harmful to humans.

Continue reading to know more about winter fly. 

What are cluster flies?

Blowfly, Blue Bottle Fly, Insect, Pest

Cluster flies have a black or silvery-black checkered body and fly around at a less frantic pace than the house fly. While they are not as annoying as other types of flies, they can still be a nuisance and should be dealt with accordingly.

Cluster flies are most active during the cooler months of the year and can often be found clustering on windows or attics. They get their name from their habit of clustering together at rest; they will overlap their wings to conserve warmth.

Cluster flies are found worldwide. They don’t cause any damage, but their bites can be a nuisance. Furthermore, they will only reproduce outdoors in the spring or fall.

However, they can leave tiny dots of excrement where they cluster. If there are large numbers inside a home, it can be quite a significant nuisance.

How long do cluster flies live?

The average lifespan of a fly is around two years. However, this can vary depending on the species of fly. Clusters flies can live as long as two years under ideal circumstances.

Where do cluster flies come from?

winter fly

Cluster flies look for a place to overwinter during the winter. It means they will search for warm places to stay, like inside the walls of your home. They can enter through very small spaces once they find a spot. They will hunker down until it’s warmer outside.

You can find cluster flies near windows and doors. They will be looking for a way inside to escape the cold weather. As the temperature outside warms, it becomes more like your home’s temperature, and the flies will start emerging from their hiding places.

Cluster flies life cycle.

Cluster flies are a common pest during the winter months. They are attracted to light and can be found near windows and doorways. They live for about 3-4 months and go through 3–4 generations.

The eggs hatch in about three days, and the larva feed for 2-3 weeks before pupating. The life cycle of the cluster fly is around two weeks. They will pupate and emerge as adults within 11-14 days.

What causes cluster fly infestation?

Cluster flies are attracted to warmth and enter buildings in the fall and winter when temperatures outside start to drop. They are mostly outdoor insects that lay eggs in the soil. The eggs hatch into larvae that eat earthworms.

Once they have depleted the food supply near their original birthplace, they search for new places to live. It often leads them into homes and other warm buildings.

Cluster flies are not an indoor problem in warm southern climates. They overwinter outside and enter buildings when the weather gets cold. They’re more common in northern states and Canada. Insect screens on windows and doors can prevent them from entering your home.

Winter Fly Problems: All You Need To Know

Cluster Fly, Mango, Fruit, Insect, Fly

Cluster flies are a species of fly that is found throughout the world. They are often mistaken for house flies, but they are a parasite of earthworms and thrive in areas with fertile soil.

They enter through cracks and crevices to ride out the winter and usually go unnoticed until one warm winter day when they start seeking to go outside again.

Cluster flies are more than just a nuisance. They can be quite annoying when they invade your home in the winter. However, they are not a danger to humans, and they do not breed in homes that they invade.

Cluster flies hibernate during the winter, but their hibernation can be interrupted by warm weather or indoor warmth.

Cluster flies are a nuisance during the winter season as they tend to fly around in large numbers. They only emerge when spring comes, and they are known to fly toward windows and sources of light before dying during hibernation.

Finally, there is the larder beetle. These beetles are attracted to the dead cluster fly and will remain in your home. Unfortunately, a professional pest control service is needed to stop an infestation from occurring.

How to get rid of cluster flies (Control)

There are a few ways to get rid of (control) cluster flies: 

  • The most effective way is to vacuum them up when you see them. 
  • You can also use flypaper to catch the flies.
  • Applying a safe and approved pesticide
  • Seal cracks around doors and windows.

Cluster flies in summer.

Cluster flies are a common household pest found both indoors and outdoors. They are most commonly seen in the late summer and early fall when they migrate into homes and buildings in search of shelter.

Cluster flies live outdoors during the summer months. But when winter approaches, they cluster together as adults and overwinter inside. Their larvae are parasitoids of earthworms during the summer months.

What do cluster flies to your home in winter?

Fly on a rotten Apple

Cluster flies and several other fly species can enter diapause during the winter. It means that they will hibernate to survive the colder weather. Females will lay eggs in safe and warm areas, such as inside walls or insulation. The adults die naturally after birth.

In winter, cluster flies can be found all around the house. They are not harmful but can be a nuisance. They are in your house because they are in diapause- a semi-dormant state that allows for the conservation of energy and heat when the temperature is not ideal.

Diapause can be short-term or long-term, depending on the species and environmental conditions.

Cluster fly vs. house fly

yellow, termite, red,

Cluster flies and houseflies are two of the most common types of flies. They are both pests, but they differ in a few ways. Cluster flies are larger than houseflies and have an audible buzzing sound.

They fly much less often than houseflies and are relatively slower. Compared to a housefly, which is relatively sluggish, cluster flies are relatively active.

Though the two fly species are attracted to different environments and food sources, they pose a problem during their respective seasons. Cluster flies tend to appear in early spring, while houseflies reach their peak during the warmest part of summer.

Both flies are drawn to plants, soil, and other food sources. As a result, homeowners need to be proactive in preventing an infestation by taking measures such as sealing off cracks and crevices around the home.

What happens to Fruit flies in winter?

Tropical Fruit Fly Drosophila Diptera Parasite Insect Pest on Ripe Fruit Vegetable Macro

Fruit flies in winter stay covered and contained. They feed off organic material. These flies bury themselves to survive until spring. It isn’t uncommon to have a fruit fly problem in the winter, so it’s best to take action quickly if you start seeing them around your home.

Do fruit flies die in winter?

The fruit fly’s lifespan decreases as the temperature decreases. At 60°F, their lifespan is about two weeks, while at 80°F, their lifespan is about 30 days.

Do flies hibernate?

Flies do not hibernate in the traditional sense as bears do. Bears sleep through the winter and go into deep hibernation.

On the other hand, Flies survive over the winter by stocking up on food in the fall. They tend to come into houses during this time of year since it is colder and can find shelter and food inside. Once they are inside, they often hibernate there until warmer weather returns.

When do flies go away?

House flies are affected by temperature just as much as young flies. The adults will die when the temperature falls below 32 degrees Fahrenheit.

Where do flies hide in the house?

Fruit flies on a banana as a close-up

House Flies will rest on floors, walls, and ceilings during daylight hours. It prefers to stay hidden from the sun.

They will rest principally on ceilings, electric wires, and dangling light cords at night. They also like plants during the day as they provide a good place to hide.

Do flies die in the winter?

Flies go through a complete metamorphosis, transforming from an immature stage to an adult. During the colder months, flies don’t die off, but they generate higher numbers during the warmer months.

Many species of flies overwinter as immature stages. They enter a resting or hibernation state until conditions are more favorable.

How do flies survive the winter?

Flies have several strategies for dealing with the cold winter weather. Some flies, like smaller houseflies, die off. However, many larger flies enter into a state of diapause, which preserves their energy and body heat.

Cluster flies are a good example of a fly that enters into diapause during the winter. They are larger than most other types of flies and can survive in colder temperatures.


Winter can be a difficult season for many reasons, including an increase in winter fly problems. Flies are prevalent in the winter months because they are looking for food and shelter. Unfortunately, this often leads to an increase in fly-related problems.

They are difficult to get rid of, but many remedies can help. Some top remedies include using fly strips, spraying vinegar or bleach, and using a vacuum cleaner. Cluster flies are becoming a more common sight during the winter season.

While they may be unsightly, they are not harmful. By understanding their behavior and biology, you can take steps to prevent them from entering your home and causing any damage.

About the author

A biotechnologist by profession and a passionate pest researcher. I have been one of those people who used to run away from cockroaches and rats due to their pesky features, but then we all get that turn in life when we have to face something.