Key takeaways
- Mosquitoes are cold-blooded and stop flying below about 50°F, so cold weather forces them into dormancy.
- Depending on the species, mosquitoes overwinter as eggs, as slow-growing larvae or as mated adult females hiding in sheltered spots.
- Some floodwater Aedes eggs can stay dormant for up to two years; Asian tiger mosquito eggs survive drying for up to a year.
- Culex females that overwinter may carry West Nile virus into spring, one leading theory for how the virus returns each year.
- In South Florida, mosquitoes stay active year-round, so winter is a slowdown, not a break.
In this article
- Why Cold Weather Stops Mosquitoes
- Diapause: The Mosquito Version of Hibernation
- Three Ways Mosquitoes Make It to Spring
- Why Only Females Survive the Winter as Adults
- What Winter Looks Like for South Florida Mosquitoes
- Where Mosquitoes Hide Around Your Home in Cooler Months
- Use Winter to Get Ahead of Mosquito Season
- Frequently Asked Questions
Mosquitoes survive winter by going dormant at whatever life stage their species is built for: some wait it out as eggs, some as slow-growing larvae, and some as mated adult females hiding in sheltered places. When warm weather returns, they pick up exactly where they left off, which is why mosquitoes seem to reappear overnight in spring.
In South Florida, the story is different. Winters here are rarely cold enough to stop mosquitoes for long, so many local species simply slow down and keep breeding. Understanding both sides helps you see why winter is the best time to get ahead of next season, not a time to forget about mosquitoes.
Why Cold Weather Stops Mosquitoes
Mosquitoes are cold-blooded insects; they cannot regulate their body temperature. As the air cools, they become sluggish. According to the Defense Health Agency, adult mosquitoes become lethargic in cold weather and stop flying below 50°F.
Before flight stops, a female has two options: lay her last eggs, or find a warm, sheltered spot to rest until spring. Which one she chooses depends on her species.
Diapause: The Mosquito Version of Hibernation
People often call it hibernation, and that is close. Scientists call it diapause: a pause in development and a slowed metabolism that lets an insect survive a hostile season.
According to the DHA, diapause in mosquitoes:
- Is biologically controlled and starts before conditions get bad, rather than as a reaction to the first freeze
- Can occur in every life stage except the pupa, depending on the species
- Stops ovary development in adult females, so they do not waste energy on eggs until spring
- In larvae, shuts down the part of the brain that drives molting, so they stop growing
There is also a simpler kind of dormancy, called quiescence. The female dies in the fall, but her eggs stay dormant until they are reactivated, then hatch when they are covered by warmer water.
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Three Ways Mosquitoes Make It to Spring
| Overwintering stage | Typical mosquitoes | Where they wait | What wakes them |
|---|---|---|---|
| Eggs | Aedes: floodwater, salt marsh and container species, including the Asian tiger mosquito in temperate areas | Dry containers, tree holes, soil in areas that flood | Rising water and warmer temperatures |
| Larvae | Some tree hole and other species | Water in tree holes and similar habitats | Warmer water speeds up growth until they emerge |
| Adult females | Culex and Anopheles | Storm drains, culverts, sheds, garages, basements, woodpiles, animal burrows | Warm days in late winter or early spring |
Eggs That Wait for Water
Many Aedes mosquitoes pass the winter as eggs. The Contra Costa Mosquito and Vector Control District explains that pasture, rainwater and salt marsh mosquitoes overwinter as eggs on plants or soil in areas that flood from rain, tides or irrigation. Some eggs hatch after one flood while others stay dormant for years, a strategy called installment hatching that protects against floods that dry up too fast.
Container mosquitoes do the same thing on a smaller scale. The CDC says Aedes aegypti eggs stick to the inner walls of containers above the waterline, can survive drying out for up to 8 months and can survive a winter in the southern United States.
Source: CDC (Aedes aegypti); UF/IFAS EDIS IN594 (Asian tiger mosquito); Defense Health Agency (floodwater Aedes)
Larvae That Grow in Slow Motion
Some species spend the winter as larvae in cold water. Contra Costa’s district describes a tree hole mosquito that hatches after the first heavy fall rains and develops so slowly that adults do not emerge until April or May. In general, larvae grow more slowly in cold water, so mosquitoes that hatch in winter may not reach adulthood until spring.
Adult Females That Hide
Culex and Anopheles mosquitoes overwinter as adults. Mated females enter diapause in late fall and shelter where they are protected from extreme temperatures, such as caves, culverts and underground storm drains. Around homes, the DHA lists sewer drains, sheds, garages, basements, logs, woodpiles and animal burrows. They emerge in late winter or early spring, take a blood meal and lay eggs.
Why Only Females Survive the Winter as Adults
The mosquitoes that overwinter as adults are mated females, and that matters because only females bite. According to UF/IFAS, female mosquitoes need blood meals to develop their eggs, while males feed only on sugar from plants. A female that survives the winter is ready to feed and lay eggs as soon as it warms up.
It also matters for disease. Culex mosquitoes are the main carriers of West Nile virus, and one leading theory, according to the Contra Costa district, is that females infected in the fall carry the virus through the winter and pass it to birds in spring. Anopheles mosquitoes, the other group that overwinters as adults, are the ones that can transmit malaria. The southern house mosquito is the principal vector of St. Louis encephalitis in the southern United States (UF/IFAS).
What Winter Looks Like for South Florida Mosquitoes
Most of that dormancy is a northern story. In South Florida, normal winter lows stay above the point where mosquitoes shut down, so the season slows rather than stops. Our guide to why mosquito season is longer than you think in Florida shows the month-by-month temperatures.
Local species reflect that. UF/IFAS notes that the Asian tiger mosquito overwinters as eggs in temperate climates but stays active year-round in tropical and subtropical habitats. Aedes aegypti, the main dengue carrier, remains common in urban South Florida, and the common house mosquito of the South is found in all 67 Florida counties.
Miami-Dade County confirms what residents notice: mosquitoes are present year-round, including a species that can transmit serious diseases, and the county runs larviciding routes in winter. When a cold front passes, activity drops for a few days; when it warms up, the mosquitoes are back. Learn more about the mosquito species common to South Florida.
Where Mosquitoes Hide Around Your Home in Cooler Months
Even in mild winters, mosquitoes look for shelter during cool spells. Check these spots:
- Storm drains, catch basins and French drains, which stay damp and protected
- Garages, sheds and utility rooms, especially if doors are left open
- Dense shrubs and ground covers close to the house
- Woodpiles, stacked lumber and clutter along fences
- Dry containers holding eggs: buckets, saucers, tires and toys that will refill in spring
Use Winter to Get Ahead of Mosquito Season
Winter is the easiest time to reduce next year’s mosquitoes, because populations are lower and the eggs are sitting still. Focus on removing those eggs before the first warm rains:
- Scrub, don’t just tip. Aedes eggs cling to container walls above the waterline, so scrub buckets, birdbaths and pet bowls, or throw out containers you do not need.
- Clean gutters and fix drainage so water cannot pool when the rains return.
- Treat water you cannot drain. Miami-Dade recommends Bti granules in bromeliads and Bti dunks in birdbaths and fountains, used as the label directs.
- Close up shelters. Keep garage and shed doors shut, and repair window and door screens.
- Keep up personal protection on warm winter days with an EPA-registered repellent.
When you are ready for help, Toro’s mosquito control service begins with a free inspection to find where mosquitoes breed and rest around your home, followed by larvicide and growth regulator treatment of breeding sites and a plant-oil barrier treatment where adults hide. The 3-month plan of 4 treatments is aimed especially at March through November, so starting before spring puts you ahead of the curve. For year-round yard habits, see how mosquitoes thrive in South Florida yards.
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305-594-4767Frequently Asked Questions
Do mosquitoes die in the winter?
How long can mosquito eggs survive without water?
Where do mosquitoes hide in the winter?
Can mosquitoes bite in winter?
Do male mosquitoes bite or survive winter?
Sources
- Where Do Mosquitoes Go During the Winter?, Defense Health Agency, Public Health
- Where Do Mosquitoes Go in Winter?, Contra Costa Mosquito and Vector Control District
- Asian Tiger Mosquito, Aedes albopictus (Skuse) (Insecta: Diptera: Culicidae), UF/IFAS Extension
- Life Cycle of Aedes Mosquitoes, Centers for Disease Control and Prevention
- Southern House Mosquito Culex quinquefasciatus Say, UF/IFAS Extension
- Miami-Dade County Mosquito Control revamps truck routes, offers winter mosquito control tips, Miami-Dade County
Educational content. This article is for general information about pests in South Florida and is not medical, legal or professional advice. If you have a bite, sting or allergic reaction, contact your doctor; in an emergency, call 911. Pest problems vary from home to home, so a licensed professional should inspect before treatment. When using any pesticide, always read and follow the product label.
