House spider sightings are expected to rise across the UK as summer gives way to autumn and temperatures begin to fall, bringing the annual return of large, fast-moving spiders inside homes.
The increase is most noticeable from late August through October, when mature male spiders leave their webs and roam in search of females. They can enter through open windows, doors, chimneys and small gaps around buildings.
Research by the University of Gloucestershire found that sightings typically peak around mid-September, with many encounters occurring in the evening. The study, based on thousands of records from across Britain, found that most of the spiders reported were males.
Experts say the seasonal surge does not necessarily mean homes are being invaded by spiders seeking warmth. Instead, the creatures are becoming more active during the mating season, making them more likely to be seen crossing floors, climbing walls or becoming trapped in baths and sinks.
The Natural History Museum says several species commonly found indoors, including giant house spiders, can have a leg span of up to 12 centimetres. Their sheet-like webs are often built in garages, sheds, lofts and cavity walls.
The warning comes after the Met Office said the UK had provisionally recorded its hottest summer on record in 2026, with an average mean temperature of 16.5C. As cooler autumn nights arrive, householders are likely to notice more of the familiar eight-legged visitors in the weeks ahead.
