Why are there no ticks in summer? - briefly
Ticks become inactive during hot, dry summer months because they need high humidity to stay hydrated and to quest for hosts; the heat and low moisture cause them to retreat into leaf litter and soil. Activity resumes when cooler, more humid conditions return in the fall.
Why are there no ticks in summer? - in detail
Ticks are most active when temperature and humidity create optimal conditions for questing, the behavior in which they climb vegetation to attach to passing hosts. During the peak of warm weather, several environmental factors converge to suppress their activity.
The main constraints are:
- Low relative humidity: Summer air often falls below the 80 % threshold required for tick water balance. Desiccation risk forces ticks to retreat to the leaf litter or soil, where they remain inactive.
- High temperature extremes: Temperatures above 30 °C accelerate water loss and can be lethal. Ticks reduce movement to conserve moisture.
- Reduced host availability: Many mammals and birds limit their activity during the hottest part of the day, decreasing opportunities for blood meals.
- Life‑stage timing: In many species, the larval and nymphal stages, which are most visible to humans, develop in spring and early summer. By midsummer, these stages have either fed and dropped off or entered a dormant phase awaiting cooler conditions.
- Behavioral adaptation: Some ticks adopt a “summer diapause,” a physiological pause that delays questing until conditions improve.
Consequently, the combination of desiccation pressure, thermal stress, limited host encounters, and developmental cycles leads to a marked decline in observable tick activity during the hottest months. When humidity rises again in early autumn, ticks resume questing, completing their seasonal pattern.