Most wasps die when temperatures drop below freezing, though the exact lethal threshold depends on the species, the time of year, and whether the wasp has had time to prepare for cold. On the heat side, wasps become fatally overheated at around 114°F (46°C). For most people asking this question, the practical answer is simpler: the first hard frost of autumn kills off an entire colony’s workers and males, leaving only hibernating queens to survive the winter.
Cold Temperatures That Kill Wasps
No single temperature kills all wasps. Different species have different cold tolerances, and that tolerance shifts dramatically with the seasons. A worker wasp in September might die at temperatures just below freezing, while a queen in the dead of January can survive brief exposures well below zero.
The key concept is the “supercooling point,” the temperature at which a wasp’s body fluids actually freeze. Once ice forms inside a wasp’s body, it dies. No wasp species studied has survived internal freezing, even when researchers deliberately triggered ice formation. The goal for any wasp surviving winter is to keep its body fluids liquid as long as possible.
For common paper wasps, supercooling points at their lowest range between about -10°C and -13°C (14°F to 9°F). That’s cold enough to survive mild winters in the southern United States but not nearly cold enough for harsh northern climates. Yellowjackets and hornets in colder regions do better. Midwinter measurements of several North American species show survival after brief exposures below -20°C (-4°F). Bald-faced hornets averaged a supercooling point of -20°C, while western yellowjackets reached -22°C (-8°F) and German yellowjackets hit -23°C (-9°F).
How Queen Wasps Survive Winter
Only queen wasps (called foundresses) survive the winter. Workers, males, and the old queen all die once cold weather sets in. The queens that make it through do so by undergoing physical changes that amount to biological antifreeze production.
As temperatures drop in autumn, queen wasps build up sugars in their blood, primarily fructose, along with other compounds like glucose and trehalose. After extended cold exposure, they also produce glycerol. These substances lower the freezing point of their body fluids, the same principle behind putting antifreeze in a car radiator. The sugars also help stabilize cell membranes and proteins at low temperatures, preventing the kind of cellular damage that would otherwise occur even above freezing.
Queens also enter winter with a thick, continuous layer of fat roughly half a millimeter thick, packed with energy reserves. This fat serves as both insulation and fuel. Workers, by contrast, lack these fat stores and the elevated sugar levels found in queens, which is why they don’t survive. Even the few workers that managed to live through cold exposure in lab studies showed no increase in protective compounds in their blood.
Shelter matters too. Queen yellowjackets overwinter under bark, stones, loose leaves, or inside building walls. These spots buffer them from the worst temperature swings. A queen tucked under bark on a -15°C night might experience temperatures several degrees warmer than the open air, and those few degrees can be the difference between staying below her supercooling point or not.
When Colonies Die in Autumn
In most of the United States and similar climates, wasp colonies collapse shortly after the first hard frost. The timing varies by region, anywhere from September in northern states to November or December farther south, but the pattern is consistent. Workers stop foraging, larvae stop developing, and the colony starves and freezes. Within days of a sustained frost, the nest is effectively dead.
This doesn’t always happen neatly on the first cold night. A brief dip to 30°F (-1°C) followed by a warm spell might slow a colony without killing it. What finishes colonies off is sustained cold that prevents foraging and drops nighttime temperatures low enough to kill workers who lack the cold-hardening chemistry of queens. Once workers die, the colony can’t feed itself or maintain the nest, and it collapses regardless of whether temperatures briefly warm up again.
Heat That Kills Wasps
Wasps are far more vulnerable to heat than most people realize. The lethal threshold is around 114°F (46°C), a temperature that’s well within the range of a hot attic in summer or a sealed car on a warm day. This is notably lower than the heat tolerance of honeybees, which can survive up to about 122°F (50°C). Japanese honeybees actually exploit this gap by swarming invading hornets and vibrating their flight muscles to generate heat, cooking the hornet to death while staying just below their own lethal limit.
For practical purposes, heat-based wasp control is difficult to apply to outdoor nests because you can’t easily raise and hold the air temperature around a nest long enough. But it explains why wasps sometimes die in enclosed spaces like greenhouses, parked vehicles, or metal sheds where temperatures spike above that 114°F mark on hot days.
What This Means Through the Seasons
If you’re dealing with an active nest in summer, temperature alone won’t help you. Wasps thrive in the same temperatures humans find comfortable, and summer heat rarely reaches their lethal limit outdoors. Your best ally is patience and the calendar. Once nighttime lows consistently dip below freezing, the colony is on borrowed time.
If you’re wondering whether a nest from last year will reactivate in spring, the answer is almost always no. The workers are dead, and the queens that survived winter will build entirely new nests in new locations. An old paper wasp nest or yellowjacket hole is just an empty structure. New queens emerging from hibernation in spring start fresh, typically when daytime temperatures reliably stay above 50°F (10°C) and food sources become available.