Seasonality and Range

This section explores when ticks are active throughout the year and how their geographic ranges are changing. Learn about seasonal patterns across major U.S. tick species and the factors reshaping where ticks are found.

In this section

  • Tick Seasonal Activity Patterns — When different tick life stages are host-seeking across the year — adult peaks in fall and spring, nymph peaks in late spring and summer, and activity on warm winter days — across the main U.S. species. Covers why the nymphal peak drives most Lyme disease cases, how species like the lone star tick and American dog tick diverge from the blacklegged tick calendar, and how warmer winters are lengthening the season.

  • How Climate Change Is Expanding Tick Ranges — Traces the mechanism by which a warming climate is shifting tick distributions poleward and to higher elevations, extending the seasons ticks are active, and redrawing the map of tick-borne disease exposure. Covers documented range shifts of Ixodes scapularis, the lone star tick, the Gulf Coast tick, and the invasive Asian longhorned tick, along with places where the literature is still genuinely uncertain.

  • The Species That Matter — geographic distribution and identification of specific tick species; this article covers seasonal activity patterns and climate-driven range expansion trends
    Not medical advice. See a healthcare provider for medical decisions. Medical Disclaimer