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Hot weather increasing the number of false widow spiders

Published 11:39 18 Aug 2026 BST

Updated 11:39 18 Aug 2026 BST

Carla Jove
Hot weather increasing the number of false widow spiders

Homenews

The hotter Irish summers are increasing the size and number of false widow spiders.

Google trends data searches for false widow spider bites have surged by 5,000% in the recent heatwave. 

The hot weather is causing the species to get bigger.

Luke Newnes, garden expert at Hillarys explains warmer conditions can accelerate spider’s breeding and growth cycles, allowing them to populate faster.  

“Unlike mammals, spiders are ectothermic, more commonly known as cold-blooded, meaning their growth, development and activity are heavily influenced by external temperatures,” he said.

“Heat speeds up their metabolism, allowing younger spiders to develop faster and adults to remain active for longer. When conditions are favourable, you can see more successful breeding, meaning local populations can build much more quickly than they would during cooler summers.

“One of the biggest misconceptions is that spiders are actively trying to get into homes through open windows. In reality, 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.”

Despite the false widow‘s white bites remain uncommon and are similar to a wasp sting, concern has grown as they keep spreading across the country.

Luke Newnes shares six ways on how to keep the spiders outside:

  1. Check and seal gaps around window and door frames.

Spiders can enter through window frames or gaps. Check those areas.

  1. Repair damaged weather seals and external cracks

Regularly check and repair small cracks on doors, windows, garages, conservatories and porches

  1. Keep vegetation trimmed away from exterior walls.

Overgrown plants climbing vegetation can provide shelter to spiders. Keep creepers trimmed to avoid them from climbing into your homes. 

  1. Reduce clutter in garages, sheds and loft spaces.

Piles of stored items and dark also provide shelter to spiders. Keep those areas clean to avoid them from nesting

  1. Limit outdoor lighting near entrances 

As lights attract insects that spiders feed on, reduce unnecessary lighting near entry points when possible

  1. Regularly remove webs around windows, doors and outdoor furniture to discourage spiders from settling

Regularly clean hiding spots and remove any spider spider webs you might find.