Swarms of flying ants emerging across Britain during the current hot spell are being picked up by weather radar and initially mistaken for rain, the Met Office has said. Because the winged insects are similar in size to raindrops and reflect light in a comparable way, they register on radar networks as what can look like showers, before closer inspection reveals them to be ants. The phenomenon matters chiefly as a quirk of how weather-monitoring technology works, and it is expected to recur as the warm weather continues.

The winged ants, known as alates, typically take to the air in hot, humid and windless conditions during July and August, though this year's early heatwave has prompted them to emerge sooner than usual. They can appear as late as September, but ant specialists Best Ants UK say the largest swarms of 2026 are predicted to fall between 20 and 25 July, noting that data from the past 24 years shows 90 per cent of nuptial flights occur in July. Met Office senior meteorologist Aidan McGivern described the appearance of the swarms as "an interesting feature" on the radar network, which detects reflections from tiny airborne particles such as raindrops — or, in this case, flying ants.