Seasonal Risk Timeline
Month-by-month tick-borne disease risk patterns and prevention guidance
Sep Prevention Tip: Adult tick season begins. Hunters and hikers should take extra precautions in wooded areas.
* indicates the current month (September)
Seasonal Insights
Spring
Mar - May
Nymph emergence period. Highest transmission risk from tiny nymph-stage ticks.
Nymphal deer ticks (Ixodes scapularis) are most active during spring. Their small size -- roughly the size of a poppy seed -- makes them extremely difficult to detect, which is why the majority of Lyme transmissions trace back to nymph encounters.
Summer
Jun - Aug
Peak season. 70% of reported Lyme cases occur during summer months.
The combination of maximum tick activity, prolonged outdoor recreation, and exposed skin creates the highest-risk window. CDC surveillance consistently shows June and July as the months with the most reported cases.
Fall
Sep - Nov
Adult tick activity increases. Second wave of deer tick encounters.
Adult deer ticks become active as temperatures cool but remain above freezing. While adults are easier to spot than nymphs, they are actively questing for hosts through leaf litter in wooded areas popular with hikers and hunters.
Winter
Dec - Feb
Low but non-zero risk. Ticks active above 35°F/2°C.
Blacklegged ticks do not die in winter. On days when temperatures rise above freezing, adult ticks can still quest for hosts. Mild winters in the Northeast and Mid-Atlantic regions increasingly extend the active season.
Monitor for mild days above 35°F when ticks may be active. Inspect firewood and pets coming indoors.
Prepare tick prevention kits as spring approaches. Stock EPA-registered repellents containing DEET or picaridin.
Begin daily tick checks after outdoor activity. Treat clothing and gear with 0.5% permethrin.
Peak nymph emergence begins. Wear light-colored clothing to spot ticks. Tuck pants into socks in wooded areas.
Highest transmission risk period. Shower within 2 hours of coming indoors. Check under arms, behind ears, and in hair.
Apply repellent before any outdoor activity. Create tick-safe zones in yards by mowing and removing leaf litter.
Full-body tick checks are essential after every outdoor exposure. Use fine-tipped tweezers for prompt removal.
Continue vigilance as Lyme risk remains high. Watch for erythema migrans (bull's-eye rash) 3-30 days post-bite.
Adult tick season begins. Hunters and hikers should take extra precautions in wooded areas.
Deer tick adults are actively questing. Keep pets on tick prevention and check them after walks.
Rake and remove leaf litter near home. Continue tick checks on warmer days above freezing.
Do not assume winter eliminates risk. Check for ticks on days above 35°F, especially in sheltered areas.
Seasonal risk data is based on historical CDC surveillance trends and entomological studies of Ixodes scapularis activity patterns. Actual risk varies by geographic region, microclimate, and year-to-year conditions. This information is educational and does not constitute medical advice. Consult local public health authorities for current tick-borne disease advisories.