Ticks are active in the fall, often surprisingly so. The period from late August through November, and sometimes into early December, represents a second distinct peak of activity, particularly for medically relevant species. Cooler, moister conditions in autumn allow certain life stages to actively search for hosts. Precautions remain necessary for anyone spending time outdoors, whether hiking or raking leaves.
Why Ticks Thrive in Cooler Weather
The decline of extreme summer heat allows ticks to flourish during autumn. Ticks are highly susceptible to desiccation and struggle in hot, dry conditions. Mild fall temperatures, typically ranging from 40°F to 70°F, provide an ideal thermal window for them to actively “quest,” or seek a host.
Moisture also plays a significant role in their survival and mobility. Increased dew, fog, and rain in autumn maintain the humidity levels ticks require to prevent drying out. While many believe the first frost eliminates the threat, ticks simply become dormant when temperatures drop below freezing. They reactivate on any warm day above approximately 40°F (4°C), extending their active season well into the winter months.
Identifying the Main Fall Threat
The main species of concern during the fall is the adult Blacklegged Tick, commonly known as the Deer Tick (Ixodes scapularis). The species’ two-year life cycle means nymphs molt into the adult stage after feeding in the spring and summer. These adults actively seek a host from October through December to secure a blood meal necessary for mating and egg production before winter.
Adult ticks are easier to spot than the poppy seed-sized nymphs, measuring about the size of a sesame seed when unfed. However, the adult Blacklegged Tick has had two previous opportunities to acquire pathogens during its larval and nymphal stages. This increased prevalence of infected adults in the fall translates to a heightened risk of disease transmission, including Lyme disease.
Essential Fall Prevention Strategies
Proper Dressing
Outdoor activities in the fall require specific preventative measures to avoid tick exposure. A simple and effective strategy involves proper dressing. Wear light-colored clothing to make ticks easier to spot and tuck pants into socks. This creates a physical barrier, sealing off the lower leg where ticks often climb upward from vegetation.
Chemical Repellents
The use of chemical repellents provides a necessary second layer of defense. Apply an EPA-approved repellent containing DEET or picaridin to exposed skin, following all label instructions. Treating clothing and gear with permethrin is highly effective, as this insecticide kills ticks upon contact and remains potent through several wash cycles. Do not apply permethrin directly to the skin.
Post-Activity Checks
Post-activity checks are the most important action, especially since the perceived threat is lower in cooler months. After returning indoors, immediately perform a thorough full-body check. Pay close attention to hidden areas like the scalp, ears, armpits, and groin. Remove all outdoor garments and place them in a dryer on high heat for at least ten minutes to kill any remaining ticks. A shower after being outside can also help wash away unattached ticks.