Ticks can survive winter conditions and continue to pose a potential risk, despite the common misconception that they disappear entirely during colder months. Understanding how they endure cold temperatures and where they seek refuge is important for maintaining safety throughout the year.
How Ticks Survive Winter
Ticks employ several biological mechanisms to survive cold temperatures, especially the blacklegged tick (Ixodes scapularis), a common vector for Lyme disease. One mechanism is diapause, an arrested state triggered by environmental cues like day length changes. This allows ticks to conserve energy and postpone development or host-seeking until more favorable conditions. Some ticks tolerate freezing temperatures by reducing body water to create a natural antifreeze. While sustained temperatures below 10°F (-12°C) can be lethal for many species, adult blacklegged ticks primarily survive by finding insulated microclimates.
Where Ticks Shelter in Winter
During winter, ticks seek sheltered environments that provide insulation from extreme cold and desiccation. Common refuges include leaf litter, dense vegetation, and under snow cover, which create protected microclimates close to the ground. Leaf litter, in particular, offers a consistent insulative barrier against winter conditions, significantly increasing tick survival. Snow cover acts as an additional protective blanket, helping to maintain a more stable temperature beneath it, shielding ticks from lethal temperatures. Some ticks may also burrow into the ground or debris, offering protection from harsh weather and allowing them to conserve energy until conditions become more suitable for activity.
When Ticks Are Active in Winter
Tick activity during winter is intermittent, largely dependent on temperature fluctuations. Blacklegged ticks can become active and seek hosts when temperatures rise above freezing, typically around 35-40°F (2-4°C). Sunny days, a lack of snow cover, or brief warm spells can trigger their activity. Adult blacklegged ticks are the primary concern for human encounters in winter, as larval and nymphal ticks are less likely to become active until warmer temperatures and longer day lengths occur. This highlights that even during winter, there is a possibility of tick exposure, especially during mild periods.
Reducing Winter Tick Risk
Reducing the risk of tick bites in winter requires continued awareness and protective measures. When spending time outdoors, wear protective clothing such as long sleeves and pants tucked into socks to help prevent ticks from attaching. Light-colored clothing can also make ticks easier to spot.
Applying EPA-registered insect repellents to exposed skin and clothing offers an additional layer of protection. After outdoor activities, thoroughly check yourself, family members, and pets for ticks, focusing on areas like the scalp, behind the ears, underarms, and ankles. Prompt removal of any attached ticks is important to reduce the risk of disease transmission.
For pets, year-round tick prevention products recommended by a veterinarian are beneficial, and regular tick checks are also advised. Maintaining a tidy yard by clearing leaf litter and tall grass can also minimize tick habitats near your home.