Why this tick season could be the worst in a decade

The 2026 tick season appears to be the worst in a decade, with CDC data showing record‑high emergency‑room visits for tick bites and experts linking the surge to milder winters, earlier springs, insulating snow cover, and abundant acorn crops that boost wildlife hosts.

This year's tick season could be one of the worst on record, according to federal data and experts.

The Centers for Disease Control and Prevention's (CDC) Tick Bite Data Tracker, which uses real‑time emergency room surveillance, shows weekly tick‑bite ER visits are higher than historic averages in every U.S. region except the South Central states, with the Northeast recording the highest levels so far in 2026.

During the fourth week of April, about 114 out of every 100,000 emergency department visits nationwide were for tick bites, the highest rate for this point in the year since at least 2017, the CDC said. Nationally, the agency estimates about 31 million people are bitten by ticks each year, and roughly 476,000 Americans are treated annually for Lyme disease, the most common tick‑borne illness.

"Tick season is here and these tiny biters can make you seriously sick," Dr. Alison Hinckley, epidemiologist and Lyme disease expert with CDC’s Division of Vector-Borne Diseases, told USA TODAY. "That means ticks are out and people are getting bitten, so now is the time for people to take steps to protect themselves and their loved ones."

While the CDC only tracks ER visits related to tick bites (not tick bites or the presence of ticks overall), the increase in these visits indicates that multiple factors, including weather, normal year-to-year variation in tick survival and expansion of tick populations into new geographic areas, could result in one of the most prolific tick-bite seasons in recent memory. However, we won’t know how this year overall will compare to other years until the season is over, said Hinckley.