Get set for a painted lady summer: big year for orange butterflies in Britain

Migrant insects have been seen in large numbers along east coast thanks to heatwave and benign southerly winds

If you’ve spotted a pale orange butterfly dashing at frenetic pace through streets, fields or gardens, you’ve noticed the new migrants that will add colour to the summer in record-breaking numbers.

What is expected to be the largest arrival of painted lady butterflies in Britain for 17 years is under way after heatwaves and favourable winds ushered thousands if not millions of the insects northwards.

The painted lady flies north from sub-Saharan Africa at the start of every year. Successive generations breed in north Africa and then the southern Mediterranean before reaching northern Europe later in the summer. In September, the offspring of these migrants fly south again .

In some summers, hardly any reach British shores, but Butterfly Conservation experts said a combination of favourable early spring conditions in southern Europe, the recent heatwave and benign southerly winds had turned 2026 into a once-in-a-decade “painted lady summer”.

“We’ve been seeing small numbers for the last three weeks but it looks like there’s been a big recent immigration from Europe over the past week, just as the hot spell collapsed,” said Dan Hoare, the director of nature recovery for Butterfly Conservation. “They grow extremely fast, feed easily and fly really well, and they’ve bred successfully in France and Spain in the heatwave and then had favourable winds to get them across the Channel.”

Painted ladies can develop from egg to caterpillar to chrysalis and emerge as an adult butterfly in as little as four to six weeks in warm weather, and so bumper generations can swiftly emerge.

The butterflies have this week been seen in large numbers along the east coast into northern England. At Hickling national nature reserve close to the Norfolk coast, 253 of the butterflies were spotted feeding on a patch of bramble flowers.