As Britain’s summers grow hotter and longer – with 2026 becoming the first year on record to hit 35°C in May, June and July – experts warn temperatures drive surges in false widows spiders.
UK searches for “false widow spider bites” have rocketed by 5,000% in the past month. Sightings are up and NHS figures show spider-related hospital admissions remain a stubborn problem. New FOI data reveals 91 admissions for spider bites in 2024, rising to 100 in 2025 – including 73 patients treated via A&E.
Garden expert Luke Newnes of Hillarys says: “Unlike mammals, spiders are ectothermic – cold-blooded – so their growth, development and activity are heavily influenced by external temperatures.”
He explains: “Heat speeds up their metabolism, allowing younger spiders to develop faster and adults to remain active for longer.
“When conditions are favourable, local populations can build much more quickly than in cooler summers.”
The noble false widow (Steatoda nobilis) is regarded as the UK’s most medically significant spider.
Bites remain uncommon and are typically no worse than a wasp sting, yet public concern has grown as the species has spread.
Mr Newnes is keen to bust one common myth: spiders are not actively seeking open windows.
He said: “They usually find their way inside through tiny structural gaps around window frames, door frames and damaged seals.
Making sure these areas are properly maintained is one of the simplest and most effective ways to reduce indoor spider activity.”
With temperatures expected to stay high, experts say simple maintenance now could spare householders an unwanted encounter later.
This story originally appeared on Express.co.uk
