The insects, known as alates, are the winged form of ants that leave their underground colonies each summer to mate
Britain's annual flying ant season has arrived earlier than usual, with swarms so large they have alerted the Met Office weather radar and have been mistaken for patches of drizzle.
The unusual phenomenon occurred as the UK recorded its highest-ever June temperature, with the recent spell of hot weather creating ideal conditions for millions of winged ants to emerge.
Meteorologists expect further false radar readings in the coming days as warm conditions continue through the third heatwave of the year this week.
The insects, known as alates, are the winged form of ants that leave their underground colonies each summer to mate.
While many people refer to a single "Flying Ant Day", experts say this is a misconception.
Swarms can occur at different times throughout the summer, typically between July and August and sometimes into September, with this year's peak expected between July 10 and July 25.
A Met Office spokesman said the insects can briefly appear on weather radar as they reflect signals in the same way as raindrops.
Large swarms can also form dense bands stretching dozens of miles, making them resemble areas of light rain or cloud.
"It is relatively common at some point in the year to see the brief influence of flying ants on radar imagery, often appearing as short-lived pockets of drizzle," the spokesman said.
Meteorologists can distinguish the swarms from genuine rainfall by comparing radar images with ground observations, which show no rain reaching the surface.
The temporary interference does not affect weather forecasts, with false alarms promptly identified.
The emergence of flying ants has been noticeable across parts of Britain, with motorists reporting windscreens covered in insects and homeowners keeping windows and doors closed despite the hot weather.
Around 90 per cent of the UK's flying ants are black garden ants.
During their annual mating flights, young queens and males leave their colonies together, mating in the air before beginning the next stage of their life cycle.
After mating, queens shed their wings and search for suitable locations to establish new colonies, while the males usually die within a day or two.
Colonies are commonly built beneath garden lawns, flower beds and patios, with mature nests capable of housing up to 20,000 ants.
Birds including swifts, swallows, house martins and seagulls take advantage of the abundance of insects, often gathering in large numbers to feed during peak swarming events.
Mark Dwelly, head gardener at Audley Stanbridge Earls retirement village in Hampshire, said the annual spectacle should be viewed as a natural part of the ecosystem, rather than a nuisance.
He said: "Flying ant day causes plenty of panic, but the idea that it all happens in a single 24-hour window is a myth. The UK experiences a flying ant season."
He encouraged gardeners to avoid pesticides and allow birds to control ant numbers naturally, noting how swarms can provide a valuable source of protein for many species.
