What temperature do aphids die?

Aphids thrive in moderate conditions, with their ideal temperature range sitting between 65–77°F. On the hot end, active aphid populations begin to die off when temperatures consistently exceed 90°F. Heat and high humidity are natural population knockdown events that can work in your favor during summer.

Cold tolerance is more complicated. Adult aphids are not cold-hardy and generally do not survive sustained temperatures much below freezing (32°F). However, aphid eggs are a different story. They are remarkably resilient and can overwinter in leaf litter and garden debris, surviving deep into sub-zero temperatures. This is why aphid populations can rebound quickly in spring even after a harsh winter.

The practical takeaway: don't rely on winter cold to solve an aphid problem. Focus on early-season biological control before populations build, and remove plant debris in fall to reduce overwintering egg sites.