When are ticks inactive during summer? - briefly
Ticks stop questing when temperatures rise above roughly 30 °C (86 °F) and humidity falls below about 50 %. Consequently, during the hottest midsummer afternoons with low moisture, they are largely inactive.
When are ticks inactive during summer? - in detail
Ticks reduce activity during the hottest parts of the day when temperatures exceed their physiological limits and ambient humidity drops below the level required for water balance. In most temperate regions, this inactivity occurs:
- When air temperature rises above 30 °C (86 °F) for extended periods.
- When relative humidity falls below 70 % for several consecutive hours.
- During midday hours, typically between 12:00 p.m. and 4:00 p.m., when solar radiation is greatest.
- In exposed habitats lacking shade or leaf litter, where ground temperature can exceed the thresholds even if air temperature is lower.
Life‑stage differences affect the timing of reduced activity. Adult females, which need blood meals for egg production, may seek shelter earlier in the day than nymphs, while larvae often remain inactive longer because of their smaller size and higher desiccation risk.
Microclimatic conditions can create pockets of continued activity. Dense vegetation, shaded leaf litter, and moist soil retain lower temperatures and higher humidity, allowing ticks to remain active even during peak heat. Consequently, activity may persist in:
- Forest understories with thick canopy cover.
- Areas near streams, ponds, or damp depressions.
- Locations with abundant moss or humus layers.
Seasonal patterns show a gradual decline in questing behavior as summer progresses and cumulative heat stress increases. By late July to early August, many populations enter a state of reduced questing, conserving energy and minimizing water loss until cooler, more humid conditions return in the evening or during subsequent rain events.
In summary, tick inactivity during summer is driven by temperature exceeding ~30 °C, humidity dropping below ~70 %, and intense solar exposure, with the most pronounced inactivity occurring in midday hours and in open, dry habitats, while shaded, moist microhabitats may sustain limited activity.