The results of the Big Butterfly Count 2026, which ran from Friday 17 July to Sunday 9 August, have recently been published.
Launched in 2010 by Butterfly Conservation, the Big Butterfly Count is a nationwide citizen science survey that helps assess the health of our environment. It has grown so much, and so quickly, that it has become the world’s biggest survey of butterflies.
This year, more than 100,000 people took part, recording almost 1.4 million butterfly sightings across the UK.
Unsurprisingly, given the summer we’ve had, the warm, sunny conditions provided excellent opportunities for butterflies to fly, feed and reproduce. The 2026 total was the second-highest recorded since the survey began. Holly blue and gatekeeper both had their best-ever years, while painted lady had its second-best and small copper its third-best.
However, where there are winners, there are inevitably losers too. Small tortoiseshell had its second-worst year since the survey began, with sightings down 66% over that period. Speckled wood were down 44% and ringlet by 39%.
Butterfly Conservation’s Head of Science, Professor Richard Fox, warned that the results may not tell the whole story: “What matters far more is what’s happening on the ground, to the butterflies’ caterpillar offspring and the plants they depend on. The very same weather that made it a good year for butterflies – lots of sunshine and very little rain – could mean we’re actually on course for a population crash, which could take years to recover from.”
The results provide a fascinating insight into how butterflies responded to the exceptionally hot and dry summer of 2026. While the heatwaves benefited some species in the short term, the prolonged heat and lack of rain can also create serious problems. Plants can dry out, reducing the nectar and food resources that butterflies and their caterpillars depend on. The full impact of this summer’s weather may not become apparent until next year.
So, a summer that was good for some adult butterflies doesn’t necessarily mean good news for butterfly populations as a whole. Some species can thrive during hot summers, while others are much more vulnerable to drought and extreme temperatures. Longer-term butterfly numbers are also influenced by changes in habitat, land management and weather patterns.
To read more about the 2026 Count, see the totals for each species and how they’ve changed compared to last year…as well as getting some suggestions on how to “drought proof” your garden just click on the link below.