Flying Ant Day 2025: Record swarms expected in UK, experts warn

Flying Ant Day 2025 is progressing to be one of the most severe in recent years, with experts warning of a prodigious number of swarms likely to take flight across the UK this summer.

The annual occurrence, when millions of ants having wings, also known as alates, arise from their colonies to pair in flight, is predicted to peak between July 22 and 25, according to Best Ants UK.

While the event normally progresses over several weeks in July and August, this year’s Flying Ant Day 2025 is expected to come earlier than usual.

The shift is associated with a blend of high humidity and alternating wet and warm weather, which creates the best conditions for swarming.

Cities are expected to face the first waves, as cities preserve more heat and speed up the ants’ mating cycle. “The heat island effect in cities like London triggers premature colony activity,” noted Best Ants UK.

Paul Blackhurst, Technical Academy Head at Rentokil Pest Control, highlighted the size of this year’s event: “Experts warn that this year could see larger-than-usual swarms of flying ants as we approach Flying Ant Day.

The alternating wet and warm weather we’ve been experiencing is creating the perfect conditions for larger-than-usual swarms, as humidity is important in keeping the ants’ wings and bodies moist during flight and mating on the wing.

Radar systems have even mistaken dense clouds of flying ants for rain in the past, highlighting the sheer volume of insects involved.

Despite the nuisance, the event plays a vital ecological role. After mating, female queens shed their wings and burrow into the soil to establish new colonies, contributing to soil aeration and serving as a food source for birds3.

With Flying Ant Day 2025 fast approaching, pest control experts advise sealing entry points, storing food securely, and installing fly screens to minimise indoor infestations.