The annual period of high bee activity, often called “bee season,” is a biological cycle synchronized with the availability of flowering plants and favorable weather conditions. This period is driven by the insects’ need to gather nectar and pollen. The question of when this season ends is not marked by a single calendar date but rather a gradual decline in activity as environmental factors change. Understanding the end of the season requires looking closely at the specific temperature thresholds and food sources that govern the lives of these diverse pollinators.
Defining the Active Bee Season
The active foraging season for most bees begins in the spring when sustained daily temperatures reliably reach 50 to 55 degrees Fahrenheit (10 to 13 degrees Celsius). These warmer conditions are necessary for the bees to be able to move and fly efficiently. This temperature rise also coincides precisely with the first major floral blooms of the year, providing the necessary food resources for colonies to begin their rapid expansion. The season is characterized by a peak in foraging and reproductive activity, typically occurring throughout the late spring and mid-summer months.
The Primary Factor Determining the End
The end of the active season is primarily dictated by a combination of two interconnected environmental shifts: a sustained drop in ambient temperature and the corresponding disappearance of forage. When average daily temperatures consistently fall below the 50-degree Fahrenheit threshold, bee metabolism and flight capability are significantly reduced. This temperature decline is accompanied by a natural floral dearth, as annual plants die back and perennial flowers cease blooming, eliminating the main sources of nectar and pollen. The lack of incoming food resources signals to social colonies and solitary bees alike that it is time to halt reproduction and begin preparing for dormancy or survival through the scarcity of winter.
Species-Specific Timelines of Decline
The timing of the decline varies significantly depending on the species’ social structure and life cycle. For social species like the western honeybee (Apis mellifera), the colony remains intact, and limited foraging may continue late into the fall on any available late-blooming flowers. The workers’ goal shifts from building population to storing sufficient honey reserves to fuel the entire colony through the winter months. Conversely, for non-social species like solitary bees and bumblebees, the decline is much more sudden in late summer or early fall. In these species, the adult males and all worker bees die off completely, concluding the annual nesting cycle; only the newly mated queen survives to find a sheltered spot for individual hibernation.
Aggressive Late-Season Insects
Much of the public’s perception of “aggressive bees” in late summer and early fall is actually due to an increase in the activity of certain types of wasps, particularly yellowjackets and hornets. These insects follow a different seasonal pattern that causes them to become nuisances around human food sources just as many bee populations are shrinking. Earlier in the season, yellowjacket workers are fed protein-rich insects by their larvae, which secrete a sugary fluid in return. By late summer, the colony stops producing new larvae, cutting off the workers’ sugar supply and forcing them to seek simple carbohydrates from other sources. This scavenging for sugars, such as those found in fallen fruit, soda cans, and outdoor dining, is why these wasps become noticeably more persistent and aggressive toward humans.
Bee Survival Strategies in Winter
Once the active season is over, bees employ strategies to survive the cold and lack of food.
Honeybee Survival
Honeybees form a tight cluster inside the hive to maintain warmth. The bees on the inside vibrate their flight muscles to generate heat, allowing the cluster to maintain a core temperature that can reach over 90 degrees Fahrenheit (32 degrees Celsius), even when outside temperatures are freezing. The energy for this thermoregulation is derived from the large stores of honey gathered over the summer and fall.
Solitary and Bumblebee Survival
In contrast, solitary bees and bumblebees rely on individual dormancy rather than collective heat generation. The newly mated queen of a bumblebee colony finds a secluded, protected location, such as under leaf litter or buried shallowly in the soil. She enters a state of diapause, a period of suspended development and lowered metabolism, where she remains motionless until the warmth of the following spring. Solitary species survive the winter as dormant larvae or pupae, protected inside the sealed, provisioned cells their mothers created, waiting for the spring thaw to emerge as adult bees.