The question of whether head lice vanish when the temperature drops is common, but the answer is clear: yes, you can absolutely get lice in the winter. Head lice are tiny, wingless parasites, unlike seasonal pests such as mosquitoes or ticks. These organisms are highly adapted to human hosts and maintain their life cycle year-round, regardless of the outdoor weather conditions. The habits people adopt during cold weather can actually increase the chances of transmission.
Lice Survival: Why Temperature Doesn’t Matter
The human head louse, Pediculus humanus capitis, is an obligate parasite that requires a human host to survive. The external temperature has virtually no effect because the louse lives close to the scalp, which provides a consistent temperature of approximately 98.6°F (37°C). This is the ideal climate for the louse to thrive and lay eggs.
Lice must feed on human blood multiple times daily and will die quickly without sustenance. An adult louse separated from a host typically survives for only 24 to 48 hours at room temperature. Nits, or lice eggs, are also dependent on the host’s warmth, meaning cold weather does not naturally kill off an existing infestation.
Increased Winter Transmission Risks
While the cold does not harm the lice, the behavioral changes during winter create ideal conditions for them to spread. People, especially children, spend significantly more time indoors, leading to closer personal contact in schools, daycares, and homes. This increased proximity facilitates the most common route of transmission: direct head-to-head contact.
The use of cold-weather accessories also introduces opportunities for indirect spread. Hats, scarves, ear muffs, and coats are frequently shared among children or piled together in communal spaces. A louse that has crawled onto a winter item can transfer to a new host when that item is worn or comes into contact with another person’s head.
Prevention Strategies for Cold Weather
Preventative steps during the colder months focus on minimizing opportunities for close contact and managing shared items. A primary defense is educating children to avoid activities that involve head-to-head contact, such as taking selfies or leaning their heads together during screen time. For those with long hair, keeping it tied back in a braid, ponytail, or bun can help reduce the surface area available for transfer during close interactions.
Managing winter gear is another important strategy to limit the spread of lice. Instructing children not to share hats, scarves, or other head-touching accessories is a simple, effective rule. In shared environments like school, it is helpful to store coats and hats separately rather than in a communal pile. If an item is suspected of being exposed to lice, placing it in a sealed plastic bag for a minimum of two weeks will ensure any surviving lice or nits die off.