Scorpions are highly dependent on external temperatures for their activity, meaning cold weather significantly alters their behavior. While they do not disappear entirely, their presence becomes far less noticeable as the season progresses. Scorpions are not equipped to handle sustained cold, leading them to seek protective shelter and dramatically reduce their movement during the winter period. Understanding this seasonal shift is important for homeowners to anticipate potential indoor encounters.
Scorpion Physiology and Temperature Response
Scorpions are ectotherms, meaning their internal body temperature is regulated by the temperature of their surroundings. Unlike mammals, they cannot generate their own heat to maintain a stable core temperature. This physiological constraint dictates their behavior, including movement and metabolism.
As the ambient temperature drops, a scorpion’s metabolic rate decreases. This slowdown conserves energy but also leads to lethargy and a reduced ability to move or hunt. Scorpions typically become inactive when temperatures fall below approximately 50°F (10°C). Below this threshold, they enter a state of deep dormancy, sometimes referred to as diapause, which is a period of minimal activity. This survival mechanism allows them to endure prolonged periods of cold and food scarcity until warmer conditions return.
Winter Behavior and Sheltering Locations
During the colder months, scorpions enter a state of dormancy, requiring them to find secure, thermally stable locations for overwintering. They are driven by an instinct to bunker down in places where the temperature remains consistent and above the threshold for activity cessation.
Outdoors, scorpions seek natural shelter in deep burrows, under landscaping rocks, beneath logs, or within debris piles. Certain species, such as the Arizona Bark Scorpion, aggregate in groups of up to 30 individuals to conserve warmth, creating what is sometimes called a “hibernacula.” These sheltered spots are often found in secluded, undisturbed spaces like wall voids, block wall fences, and under concrete slabs.
The search for thermal protection often directs scorpions toward human structures, making them a concern for homeowners. They can enter a home through tiny openings, needing only a crack as wide as a credit card to gain access. Once inside, they gravitate toward warm, quiet areas such as attics, crawl spaces, wall voids, and gaps around pipes. Finding a scorpion indoors during the winter months, typically November through February, suggests a potential nesting site is nearby, where a group is overwintering.
Activity During Intermittent Warm Spells
While scorpions are generally inactive in winter, they occasionally emerge briefly if the weather permits. On unusually warm winter days, a spike in temperature can be enough to raise their body temperature and rouse them from their dormant state. This temporary emergence is often an attempt to bask in the sun to elevate their temperature or to search for water.
For scorpions overwintering inside a heated structure, their activity may be triggered by the stable, artificial warmth. Areas near heat sources like furnaces, water heaters, or interior walls can keep them semi-active throughout the season. A scorpion seen inside a home during the winter is often moving between a cold hiding spot and a warmer one. This is when the risk of an encounter is highest, as the arachnids may wander into living spaces while seeking a more stable thermal zone.