What time of year are ants most active?

Ants are most active during spring and summer, with peak activity typically occurring from April through September in most parts of the United States, though exact timing varies by species, climate, and region, and some species remain active year-round in heated homes. Ant activity begins increasing in early spring, March through May, as temperatures rise above 50 degrees Fahrenheit and overwintering colonies become active, with queen ants increasing egg laying and worker ants intensifying foraging for food to support colony growth, so you start seeing odorous house ants and carpenter ants scouting into kitchens. Late spring to early summer, May and June, is when ant activity sharply increases because colonies are growing rapidly and need more food, and carpenter ants swarm in spring to establish new nests. Summer, June through August, is the most active period overall because heat accelerates ant metabolism and reproduction, so colonies need more food and expand faster, with fire ants, pavement ants, Argentine ants, and odorous house ants highly active outdoors and indoors forming long trails. Fall, September through October, sees a second surge indoors as ants seek warmth and food before winter, though outdoor activity begins to decline as temperatures drop. In warm southern states, ants remain active longer from February to November due to mild winters, while in northern states season is shorter April to September. In heated homes, odorous house ants and pharaoh ants can be active year-round. For prevention, early spring March to May is best time for barrier treatments.