When does the summer tick season start? - briefly
In most of the United States, the summer tick activity begins in early May, when temperatures consistently rise above 50 °F (10 °C). In warmer regions it may start in late March, while cooler areas can see the onset as late as June.
When does the summer tick season start? - in detail
The summer activity of ticks generally begins when temperatures consistently rise above 50 °F (10 °C) and relative humidity exceeds 80 %. In most of the United States, this threshold is reached in late April to early May, though the exact timing varies by region and species.
- Northeast and Midwest: Tick activity typically starts in the third week of April. The blacklegged tick (Ixodes scapularis) emerges first, followed by the American dog tick (Dermacentor variabilis) a few weeks later.
- Southeast: Warm climate accelerates emergence; activity can begin as early as mid‑March. Lone‑star ticks (Amblyomma americanum) become active shortly after the first sustained warm days.
- Mountain West: Higher elevations delay the onset. Tick activity often does not commence until late May or early June, depending on snowmelt and daytime temperatures.
- Pacific Northwest: Coastal areas experience early activity, usually in early May, while inland valleys may see the start in mid‑May.
Key environmental drivers include:
- Temperature: Sustained daytime highs above 60 °F (15 °C) stimulate questing behavior.
- Humidity: Moisture levels above 80 % prevent desiccation, allowing ticks to remain active on vegetation.
- Photoperiod: Longer daylight periods trigger developmental cycles, especially for larvae and nymphs.
- Host availability: Increased activity of deer, rodents, and domestic animals in spring provides feeding opportunities, prompting ticks to emerge.
Monitoring local weather data and consulting regional health department reports can pinpoint the precise start of tick activity in a given area. Early detection of the seasonal shift enables timely implementation of personal protection measures and landscape management to reduce exposure risk.