Tick season in the United States peaks in May and June, but ticks can be active any month of the year when temperatures rise above freezing. The traditional idea of a neat summer-only tick season is misleading. Different tick species are active at different times, and regional climate plays a major role in when your risk is highest.
When Tick Season Starts and Peaks
Spring marks the beginning of what most people recognize as tick season. Adult blacklegged ticks left over from the fall are still active, while American dog ticks and lone star ticks wake up and flood the landscape. May is consistently the “tickiest” month of the entire year across the country, and the highest risk for tick-borne disease runs from May through August.
But focusing only on summer gives you a false sense of security. Blacklegged ticks, the primary carriers of Lyme disease, are active from October through May as long as daytime temperatures stay above freezing. Their peak activity actually happens in the fall, when cooler temperatures are ideal for them. This catches many people off guard, especially hikers and hunters who assume the first frost means ticks are gone.
Why Ticks Don’t Follow a Simple Calendar
Ticks go through multiple life stages, and each stage has its own active window. The younger nymph-stage blacklegged ticks become active in late spring and stay active through summer. They’re roughly the size of a poppy seed, making them extremely easy to miss on your skin. Both nymphs and adult females transmit Lyme disease, babesiosis, and anaplasmosis.
American dog ticks follow a more predictable pattern. They start questing (actively searching for a host) as days get longer in spring and early summer, then taper off as days shorten in late summer and fall. Lone star ticks follow a similar warm-weather pattern, exploding onto the scene in spring alongside American dog ticks.
The key number to remember is 4°C (about 40°F). Adult blacklegged ticks start looking for a host whenever temperatures hit that threshold. That includes mild days in the middle of winter. If the ground thaws and temperatures creep above freezing for even a day or two, unfed adult ticks can resume questing for a blood meal.
Tick Activity by Region
Where you live changes your tick season dramatically.
In the Northeast and Upper Midwest, fall is a second peak season that surprises people. Adult blacklegged ticks seem to appear out of nowhere after the first frosts, right when people feel safe going outside again. Spring through summer brings nymph activity and the arrival of dog ticks and lone star ticks, creating a long exposure window from roughly April through November.
In the South, warm temperatures mean ticks can be active nearly year-round. There’s no hard winter freeze to shut down activity for months at a time, so vigilance needs to be more constant.
On the West Coast, winter is actually a notable tick season. Western blacklegged ticks are reported frequently in California, Oregon, and Washington during December through February, when much of the rest of the country sees reduced activity due to snow cover and cold.
How Ticks Survive Winter
Ticks don’t hibernate. They enter a low-energy state and wait for conditions to improve. Their cold tolerance is remarkable. Blacklegged ticks can survive temperatures as low as -10°C (14°F), and some individuals endure down to -21.7°C (-7°F) by pulling water out of their cells before it crystallizes into ice.
Winter actually provides some advantages for ticks. Shade, moisture, and thick layers of fallen leaves create ideal sheltering conditions. Ticks nestle into leaf litter and wait. Larvae and nymphs that haven’t fed yet typically stay dormant until spring. But unfed adults are more aggressive. They can mobilize and start questing during any brief warm spell, even if snow is still on the ground nearby. The catch is that the ground beneath them needs to be thawed and they can’t be buried under snow.
Protecting Yourself Throughout the Season
Two products form the backbone of tick prevention, and they work differently. DEET is a repellent you apply directly to exposed skin. It needs to be reapplied every two to three hours in warm weather. Spray it on and let it dry in place. It’s safe for both adults and children.
Permethrin is a pesticide that goes on your clothing, not your skin. It binds to fabric and only needs reapplying every few months, making it a practical choice for people who spend a lot of time outdoors. Treating shoes, socks, and pant legs is especially effective since most ticks latch on from ground level.
When choosing a product, look for EPA-registered options that list protection time on the label, the specific insects they protect against, and the percentages of active ingredients. Using both DEET on skin and permethrin on clothing gives you layered protection.
Beyond repellents, doing a thorough tick check after spending time outdoors remains one of the most effective defenses. Pay attention to hidden areas like behind the ears, along the hairline, under arms, and behind knees. Nymph-stage ticks are tiny enough to look like a freckle or speck of dirt, so checking carefully matters more than checking quickly. Showering within two hours of coming indoors and tossing clothes in a hot dryer for 10 minutes can kill ticks you haven’t spotted yet.
The Bottom Line on Timing
If you live in the Northeast or Midwest, your highest-risk window runs from April through November, with a summer peak from nymphs and a fall peak from adults. In the South, year-round awareness is warranted. On the West Coast, winter months carry real risk from western blacklegged ticks. Across the entire country, any day above freezing can be a tick day. The safest approach is treating tick prevention as a habit tied to outdoor activity rather than a seasonal checklist.