FleaDates › Tick season › Delaware
Southeast · DE
When are ticks active in Delaware?
Ticks in Delaware are typically active mid-February to mid-December, heaviest Apr–Oct — and adult blacklegged ticks can surface on any mild winter day.
Ticks to know in Delaware
For such a small state, Delaware packs in serious tick variety: blacklegged ticks drive Lyme concern statewide, while lone star ticks are notoriously thick in the wooded southern half toward the beaches. American dog ticks work the open field margins and mowed yard edges from late spring through summer. Pressure climbs from April, holds high through October, and blacklegged adults keep questing on mild days into December.
Wherever the calendar sits this month, the habit that actually catches ticks is the after-walk check: ears, collar line, armpits, between the toes. Prevention plus checks beats either alone.
Month-by-month tick activity in Delaware
| Month | Typical activity | Average temperature |
|---|---|---|
| January | Low | 34.8°F |
| February | Low | 36.9°F |
| March | Moderate | 44.1°F |
| April | High | 54.7°F |
| May | Peak | 64°F |
| June | Peak | 72.9°F |
| July | Peak | 77.8°F |
| August | Peak | 76°F |
| September | Peak | 69.5°F |
| October | High | 58.2°F |
| November | Moderate | 47.7°F |
| December | Low | 39.3°F |
Estimates from NOAA U.S. Climate Normals (1991–2020), averaged across 2 weather stations near Delaware's larger cities, using the ~40°F activity threshold reported in published tick research. Real years run early or late with the weather.
Fleas peak later. Delaware flea season typically runs late March to mid-November — see the Delaware flea season page.
Frequently asked questions
When does tick season start in Delaware?
Around mid-February in a typical year, once temperatures clear roughly 40°F — noticeably earlier than flea season. A February thaw can bring ticks out ahead of schedule.
What ticks live in Delaware?
The species dog owners most often meet in Delaware: blacklegged (deer) tick, lone star tick, American dog tick. For such a small state, Delaware packs in serious tick variety: blacklegged ticks drive Lyme concern statewide, while lone star ticks are notoriously thick in the wooded southern half toward the beaches. American dog ticks work the open field margins and mowed yard edges from late spring through summer. Pressure climbs from April, holds high through October, and blacklegged adults keep questing on mild days into December.
Do I need tick prevention in winter in Delaware?
Yes. Ticks overwinter under leaf litter and snow rather than dying off, and mild spells wake them — which is why veterinary organizations recommend year-round parasite prevention. The calendar shows when pressure peaks, not when protection can lapse.
What about fleas in Delaware?
Fleas run on a warmer calendar — in Delaware that's late March to mid-November. See the Delaware flea season page for that month-by-month picture.