Breeding stops: below about 11 °C (Da Lage et al. 1989). Chill coma: flies kept warm stop moving at about 3.4–8.3 °C and recover if warmed soon (MacMillan et al. 2016, 2017). How long they last: half of adults die within 29–60 hours at 0 °C, and none survived 2 hours at -5 °C (Czajka & Lee 1990). Indoors: a heated home keeps them breeding all year (University of Kentucky).
Do fruit flies die in winter?
Outdoors, many do — and the ones that don't stop breeding. Fruit flies are cold-blooded, so their bodies run at the temperature of the air around them. As autumn turns to winter, three things happen in order: development of eggs and larvae stops near 11 °C (52 °F) (Da Lage et al. 1989), adults fall into a reversible "chill coma" a few degrees lower, and long spells near freezing kill them. So when people ask do fruit flies die in the winter, the honest answer is "the outdoor population shrinks to a few survivors, but it doesn't vanish".
Do fruit flies die in cold weather, then? Given enough time near freezing, yes — but a single cool day mostly just stops them breeding.
Indoors is a different story. A heated kitchen at 20 °C (68 °F) is summer weather for a fruit fly. The University of Kentucky notes that fruit flies "can be a problem year round", even though they are most common in late summer and autumn. Will fruit flies die in winter inside your home? Only if the house is cold enough or the breeding source is gone — the weather outside makes no difference to flies breeding in your fruit bowl.
- Outdoors in a cold winter: no breeding, most adults die, a few survive as adults in sheltered places (Hoffmann et al. 2003).
- Unheated garage, shed or porch: too cold to breed for most of the winter; adults and eggs on stored fruit can wait it out.
- Heated home: business as usual — new flies about every 11 days at 22 °C (Bloomington Drosophila Stock Center).
What temperature kills fruit flies?
There isn't one magic number, because time matters as much as temperature. Here is the answer to what temperature do fruit flies die at, and how fast, from lab studies of Drosophila melanogaster:
| Temperature | Adults | Eggs and larvae | How long adults last |
|---|---|---|---|
| 25 °C (77 °F) | Active and breeding | Egg to adult in 9 days | 38–63 days (lab average) |
| 21 °C (69.8 °F) | Active and breeding | Egg to adult in 13 days | 72–116 days (lab average) |
| 18 °C (64.4 °F) | Active and breeding | Egg to adult in 19 days | 97–134 days (lab average) |
| 15 °C (59 °F) | Slowed down | Slower than 19 days; stops near 11 °C | 120–142 days (lab average) |
| 11 °C (51.8 °F) | Slowed down | Slower than 19 days; stops near 11 °C | 152 days (lab average) |
| 9 °C (48.2 °F) | Not breeding | Development paused | Not timed — cold harms them below 11 °C |
| 4 °C (39.2 °F) | Chill coma | Development paused | 13–83% recovered after 4 days at 4 °C |
| 0 °C (32 °F) | Dying | Larvae: half dead in 8 min–3.2 h | Half dead after 29–60 hours at 0 °C |
| -5 °C (23 °F) | Dies within hours | Larvae and pupae killed within 2 hours | None survived 2 hours at -5 °C |
| -18 °C (-0.4 °F) | Dies within hours | Larvae and pupae killed within 2 hours | None survived 2 hours at -5 °C |
Rows from 11 °C up use the same lifespan figures as our fruit fly lifespan calculator and the same development times as the life cycle calculator. Below that, the figures come from cold-tolerance studies: MacMillan and colleagues (2016, 2017), Pool and colleagues (2017), Koštál and colleagues (2011) and Czajka and Lee (1990).
How cold does it have to be to kill fruit flies?
For a quick kill, it has to be below freezing. At 0 °C (32 °F), half of the adults in a 2017 study were dead after 29.2 hours if they had been kept warm, and after 59.5 hours if they had spent time at 10 °C first (MacMillan et al. 2017). At -5 °C (23 °F), no adult that had been kept warm survived 2 hours (Czajka & Lee 1990). Above freezing, cold mainly stops them breeding; it kills slowly, over days.
So how cold does it have to be to kill fruit flies in practice? A night just below freezing kills many adults; a cool autumn week at 8–10 °C mostly just stops them breeding.
Can fruit flies survive the cold? Chill coma explained
Yes, for a while. Can fruit flies survive cold spells? They can survive a few hours to a few days of cold by shutting down. Scientists call it chill coma: at a temperature called the critical thermal minimum, the fly's nerves and muscles stop working and it falls over, unable to move (MacMillan et al. 2016). It isn't sleep or hibernation — it's paralysis — and as long as it doesn't last too long, the fly gets up again when it warms.
At what temperature do fruit flies stop moving?
It depends on what the fly is used to, which is why we give a range rather than one number:
- Flies kept warm (like kitchen flies): chill coma at about 3.4 °C in flies kept at 21.5 °C (MacMillan et al. 2016) and about 8.3 °C in flies kept at 25 °C (MacMillan et al. 2017).
- Flies that have adjusted to cold: about 5.3 °C after time at 10 °C, and as low as 0.9 °C after six days at 6 °C.
- Raised in the cold: flies that grow up in cooler conditions resist cold better too — the chill-coma temperature drops by about 1 °C for every 4 °C cooler they were reared (Gibert & Huey 2001).
Long before chill coma, flies slow down. Flies kept warm lose the ability to fly at around 14–18 °C (MacMillan et al. 2016), which is why fruit flies on a cold windowsill tend to walk rather than take off.
Can fruit flies survive in the cold if it lasts?
Not indefinitely. While a fly is in chill coma it slowly loses control of the salts and water in its body, and this leads to cell damage and death (MacMillan et al. 2016). Short spells are fine: after 6 hours at 0 °C, flies stood up again 15–28 minutes after warming (MacMillan et al. 2017). Long spells are not: after 4 days at 4 °C, between 13% and 83% of females could still stand or move, depending on where their ancestors came from — flies from France did best, flies from lowland Ethiopia worst (Pool et al. 2017). So can fruit flies survive the cold? Overnight, often; for a week near freezing, rarely.
Do fruit flies die in the fridge or freezer?
A fridge set to 4 °C (40 °F), the temperature the FDA recommends, sits right in the chill-coma zone. Adults that get shut in with the fruit stop moving within minutes and start to suffer cold injury. How long do fruit flies live in the fridge? The best measurement we found is the 4 °C test above: after 4 days, 13–83% were still alive. So most adults die within days, not weeks, and some are revived when you take the fruit out.
Can fruit flies survive in the fridge long enough to breed?
No. Development stops below 11 °C, so can fruit flies survive in the fridge and multiply there? They can't: nothing hatches, grows or emerges while it stays cold. This is why extension services advise refrigerating ripe produce — the University of Kentucky says ripened produce "should be eaten, discarded or refrigerated", and UConn Extension notes that refrigeration keeps eggs from hatching.
Do fruit fly eggs survive the cold?
Possibly — and this is the catch. Does refrigerating fruit kill fruit fly eggs? We found no study that timed how long fruit fly eggs survive at fridge temperatures, so we can't say that it does. What we know about the other young stages:
- Larvae are fragile at 0 °C: half of those raised at 25 °C died within about 8 minutes, and half of those raised at 15 °C within about 3 hours (Koštál et al. 2011).
- At 5 °C, larvae that had been raised cool lasted longer: half were still alive after about 32 hours (Koštál et al. 2011).
- Pupae were killed by 2 hours at -8 °C (Czajka & Lee 1990).
So treat the fridge as a pause button, not a cure: fruit that flies have visited should be washed, trimmed or thrown out.
Do fruit flies die in the freezer?
Yes. A home freezer runs at about -18 °C (0 °F) (FDA). Fruit flies are "chill susceptible": their body fluids don't freeze until about -20 °C, but the cold kills them long before that. Unprepared adults didn't survive 2 hours at -5 °C, no larvae survived 2 hours at that temperature, and pupae died after 2 hours at -8 °C (Czajka & Lee 1990). Do fruit flies die in the freezer, then? Every stage is far beyond its limit within hours.
Why do fruit flies disappear in winter, and where do they go?
Do fruit flies disappear in winter? Outdoors, they become very hard to find, for three reasons:
- No breeding. Below about 11 °C, eggs and larvae stop developing, so no new adults replace the ones that die.
- Females pause egg production. Under short days at 12 °C, female fruit flies enter a resting state called ovarian diapause, in which their eggs stop maturing until it warms up (Saunders et al. 1989, 1990).
- Cold deaths. Frosty nights and long spells near freezing kill adults that are caught out in the open.
Where do fruit flies go in the winter? The survivors stay put as adults. In temperate areas, "Drosophila melanogaster persists over winter at the adult stage" (Hoffmann et al. 2003). It needs sheltered spots that stay a little warmer than the open air — the sort of places near people, such as outbuildings and stored produce, where conditions don't swing as hard.
Do fruit flies hibernate?
Not in the way a hedgehog does. Do fruit flies hibernate? Their winter state is a mix of the two things above: females switch off egg-laying (diapause), and on cold days every fly sits motionless in chill coma. Both are temporary; neither is a deep sleep that carries them safely through freezing weather. That's why most outdoor flies die, and a few sheltered adults carry the population through. So how do fruit flies survive winter? As dormant adults in sheltered places, not as hidden eggs.
So do fruit flies go away in the winter? Outdoors, mostly yes. Indoors, they only go away when their breeding source does.
Why you can still have fruit flies in your house in winter
If you're wondering why do I have fruit flies in winter, it's because your home is giving them summer conditions. At 20–22 °C, a generation takes only 11 days at 22 °C, adults live for weeks, and every forgotten onion, slimy drain or unrinsed bottle in the recycling is a nursery. The outdoor cold never reaches them.
Fruit flies in the house in winter usually come from one of these:
- Produce brought in from outside. Fruit and vegetables from the shop or a winter store can carry eggs and larvae (University of Kentucky).
- A breeding spot that never went away. Drains, bins and damp mops keep a colony going all year.
- Holiday fruit bowls, cider, wine and home brewing, all of which ferment in a warm room.
The fix is the same in January as in August: remove the source. Our fruit fly die-off timeline tells you how many days the last adults should take to disappear once you have.
Do fruit flies come back in spring?
Yes — from the survivors. Adults that made it through winter start laying again as it warms. In outdoor cages through a temperate winter, egg-laying rose abruptly in late winter (Hoffmann et al. 2003), and populations from cold places did this best. Because a generation takes only about 19 days at 18 °C and 9 days at 25 °C, a handful of spring survivors can rebuild a large population by late summer — which is why fruit flies are "especially common during late summer/fall" (University of Kentucky).
So do fruit flies come back in spring into your kitchen? Usually with produce, or through open windows. Tight 16-mesh window screens and prompt refrigeration of ripe fruit keep the spring arrivals from settling in (University of Kentucky).
Garden fruit flies (Medfly) in winter
In some countries "fruit fly" means a crop pest, not a kitchen fly. The Mediterranean fruit fly (Ceratitis capitata) belongs to a different family, the Tephritidae, and lays its eggs inside ripening fruit. Its winter survival depends heavily on how cold the winter is:
| Kitchen fruit fly (Drosophila) | Mediterranean fruit fly (Ceratitis) | |
|---|---|---|
| Where it overwinters | As adults, in sheltered spots (Hoffmann et al. 2003) | All stages in a mild winter: adults, eggs or larvae in fruit, pupae in soil (Rahman & Broughton 2019) |
| Mild winter (Perth, Western Australia) | — | Adults caught all year but very few in winter; caged adults lived 72–110 days |
| Cold winter (Vienna, Austria) | — | No stage survived outdoors; some of every stage survived in an unheated basement (Wernicke et al. 2024) |
| Comes back in spring from | Adults that survived winter | Surviving adults, eggs in fallen fruit and pupae in the soil |
The Western Australian study recommends removing fallen fruit, especially apples and winter citrus, because eggs and larvae inside it carry the pest through to spring (Rahman & Broughton 2019). For the kitchen fly's own development, see the fruit fly life cycle.
Gnats behave differently in winter — fungus gnats in houseplant soil, for example, keep breeding indoors for their own reasons. The gnat winter calculator covers fungus gnats, drain flies and phorid flies.
How this fruit fly cold calculator works
The calculator places your temperature in one of seven sourced bands and builds the answer from the same data as our other fruit fly tools:
- Above 30 °C: outside our cold data; it points you to the lifespan calculator.
- 18–30 °C — active and breeding: adult lifespan from the lifespan calculator's lab data (Mołoń et al. 2020; Massie et al. 1985) and egg-to-adult time from the Bloomington Drosophila Stock Center (18–29 °C).
- 11–18 °C — slowed down: lifespans from the same data; development slower than at 18 °C.
- 8.3–11 °C — too cold to breed: development stops below 11 °C (Da Lage et al. 1989).
- 0–8.3 °C — chill coma: the upper chill-coma temperature for flies kept warm (MacMillan et al. 2017), with the 4 °C survival test (Pool et al. 2017).
- -5 to 0 °C — likely to die within 1–2½ days: the 0 °C results (MacMillan et al. 2017).
- At or below -5 °C — likely to die within 2 hours (Czajka & Lee 1990).
Where the flies are changes the advice, not the numbers: picking the fridge or freezer fills in the FDA's recommended setting, and the others fill in an example you should change. For temperatures from 11 to 30 °C the result also shows how long adults last with no food, from the same equations as our die-off timeline (Da Lage et al. 1989). Temperatures from -30 to 45 °C are accepted; anything else is rejected rather than guessed.
Frequently asked questions
Do fruit flies die in the winter?
Outdoors, most do: breeding stops below about 11 °C, adults fall into chill coma a few degrees lower, and long spells near freezing kill them. A few adults survive in sheltered spots. Indoors, heated homes let them breed all year.
What temperature kills fruit flies?
Freezing kills them fastest: at 0 °C half of the adults die within 29–60 hours, and at -5 °C none survived 2 hours. Between 0 and 11 °C cold stops breeding and kills slowly, over days.
Can fruit flies survive in the fridge?
Not for long, and they can't breed there. At 4 °C they fall into chill coma; after 4 days at 4 °C only 13–83% of adults recovered (Pool et al. 2017).
How long do fruit flies live in the fridge?
Days rather than weeks. Some revive if the fruit is taken out within hours; after 4 days at 4 °C most have died, depending on the strain.
Do fruit flies die in the freezer?
Yes. A freezer at -18 °C is far below the -5 °C that killed adults and larvae within 2 hours, and the -8 °C that killed pupae (Czajka & Lee 1990).
Why do I have fruit flies in winter?
Because your home is warm. At 22 °C a new generation appears about every 11 days, so a fruit bowl, drain or recycling bin keeps them going whatever the weather outside.
Do fruit flies go away in the winter?
Outdoors they mostly disappear: they stop breeding, females pause egg production and many adults die. Indoors they only go away when the breeding source is removed.
Where do fruit flies go in the winter?
The survivors overwinter as adults in sheltered places that stay a little warmer than outside (Hoffmann et al. 2003). They don't hide as eggs.
Do fruit flies hibernate?
Not true hibernation. Females stop maturing eggs under short days at 12 °C (diapause), and in the cold all adults sit motionless in chill coma until it warms.
Does refrigerating fruit kill fruit fly eggs?
It stops them hatching, but we found no study showing it kills them. Wash, trim or throw out fruit that flies have visited instead of relying on the fridge.
Can fruit flies survive cold weather outside?
Briefly. Flies kept warm stop moving at about 3.4–8.3 °C, and cold-adjusted flies at 0.9–5.3 °C. They recover from short spells but die after days near freezing.
Do fruit flies come back in spring?
Yes. Adults that survived the winter start laying again as it warms — egg-laying jumps in late winter — and numbers peak in late summer and autumn.
These calculators give estimates for education. Real flies vary with strain, food, humidity and temperature. For a stubborn infestation, your local cooperative extension service can help identify the insect. We give no pesticide advice.