Flying Ant Day 2026: what actually happened in the UK

If you went looking for one in Britain this year, you had options.

Merlin Environmental, working from their own 2017 to 2025 sighting records, put the likely window at 7 to 20 July. Country Living ran 20 to 25 July. Best Ants UK, who publish by far the most detailed prediction of the lot, went for 24 to 29 July, with the biggest swarm on the 26th and a smaller follow-up around 2 August. Plenty of regional papers split the difference and printed "10 to 25 July".

Line those up and they cover most of a month. For an event described as a day, that's a strange result.

None of it is carelessness. They're all reading the same weather and mostly the same species, and the honest range genuinely is that wide. The spread is the finding.

They went early.

The first winged black garden ants of 2026 were reported on 21 June, after a second heatwave in as many months had brought colonies on well ahead of schedule. A larger wave followed on 5 July as the third heatwave built.

Then on 8 July, with London forecast into the mid thirties, the swarms got thick enough to turn up on Met Office weather radar as bands of something that looked like light drizzle. Alates are roughly raindrop-sized and bounce the beam back much the same way, so a big enough flight reads as weather until a forecaster cross-checks it against gauges on the ground and finds nothing falling. Fox Weather ran it on the 8th, which is about when the story does the rounds most summers: Kent and Sussex in 2020, northwest of London in 2025.

That was sixteen days before the first of the predicted windows opened.

By the time Flying Ant Day week came round, a substantial share of the country's queens had already gone up, come down, shed their wings and started digging.

The Royal Society of Biology ran a citizen-science flying ant survey across 2012, 2013 and 2014, and the results are still the best answer anyone has. Flying ants were reported somewhere in the UK on 96% of days between the start of June and the start of September.

Not 96% of summers with a big day in them. 96% of days.

They also found no meaningful geographical coordination. One garden gets its flight; the garden two streets over gets one a fortnight later, and both are normal. The pattern changed hard between years too, which is the part that dooms any calendar-based prediction: in 2012 something like 80% of the activity fell into a few days in late July and a few more in mid-August, and other years smear out across the whole season.

Adam Hart of the University of Gloucestershire, who led the analysis, put it plainly to the Mirror on 22 July: "Sometimes you could have ants flying in your garden weeks after each other. So, in a good summer, you can actually have lots of flying ant days throughout that period."

2026 was a good summer by that definition, and then some.

The Met Office half-season review, published on 16 July, has the numbers. UK mean temperature for 1 June to 15 July running 1.8 °C above the long-term average, and 2.4 °C above in England. More days above 30 °C already than the whole of 1976. The first year on record to reach 35 °C in May, June and July. Rainfall at 42% of the seasonal average.

Warmth like that doesn't shift the flight season sideways so much as widen it. Ants need it above about 13 °C with wind under 6.3 m/s, and in a normal British summer those two conditions are the bottleneck: you get a handful of qualifying afternoons and every colony piles into them at once, which is what makes a "day" look real. Give the same colonies dozens of qualifying afternoons and they spread out.

Which is more or less what we watched happen.

The dryness may have pulled the other way. Flights tend to come a day or two after rain, when the ground has softened enough for a founding queen to dig, and there wasn't much rain to come after.

Forecasters expected the heat to ease around 26 and 27 July as low pressure moved in, which would make the back end of the most-quoted prediction window a poor bet on the weather rather than a good one.

That doesn't close the season. Lasius niger will take a warm, humid, still afternoon whenever one turns up, and there are usually a few left in August. And August isn't really their month anyway: Lasius flavus, the yellow meadow ant, tends to go up in the second half of it, out of lawns and old grassland, in flights that are smaller and easier to miss and honestly nicer to watch.

So if you missed the whole thing, you haven't.

A date is the wrong unit. What you want is the odds where you are, on the afternoon you're actually standing there, for the species that lives near you. That's a forecast, and it looks different in Southampton and in Newcastle on the same Tuesday.

Dealate scores those odds from live weather, species by species, and shows the reasoning behind the score rather than asking you to take it on faith. A reason to look up, not a guarantee.

This post gets added to as the rest of the season plays out.

25 July: written. Two national waves already flown, a third predicted for this week against a forecast that's turning cooler.