False widow spiders originally come from the Canary Islands and Madeira, but they’ve spread across Western Europe, parts of the Mediterranean, and into pockets of North America and South America. The most commonly discussed species, the noble false widow, is now well established in the UK, Ireland, and southern California, with its range still expanding. Where you’ll find them depends on both geography and the kind of shelter available nearby.
Native Range and Global Spread
The noble false widow (the species behind most headlines) likely originated in the Canary Islands and Madeira, volcanic archipelagos off the northwest coast of Africa. From there, it spread throughout Western Europe and the Mediterranean, almost certainly hitchhiking in cargo shipments and imported goods. Central European populations weren’t even documented until 2011, which gives a sense of how recently this spider has been turning up in new places.
Beyond Europe, established populations now exist in California and parts of South America. In California, the noble false widow has been collected in Monterey, San Diego, Alameda, and Ventura counties. These introductions follow the same pattern: the spiders arrive through trade routes and settle in mild coastal climates that resemble their native habitat.
Where They Live in the UK and Ireland
The UK is where false widow spiders get the most public attention, and for good reason. The noble false widow is now well established across England’s southern counties and is steadily spreading north. Every autumn, reports spike as the spiders move indoors or become more visible around homes. Ireland has also seen significant colonization.
The noble false widow isn’t the only species in the UK, though. The cupboard spider is widespread across England, Wales, and Ireland, and extends through much of northern Europe. The rabbit hutch spider is even more common, found throughout Britain and northern Europe. A fourth species, the Mediterranean false widow, isn’t established in Britain but gets repeatedly imported with produce from the Mediterranean, particularly grapes. So even if it doesn’t maintain a permanent population, it regularly shows up.
Habitats Around Your Home
False widows are strongly associated with human structures. They favor sheltered, undisturbed spots: garden sheds, window frames, dark corners inside houses, garages, and conservatories. Their webs are messy, tangled structures made of non-sticky but very strong silk, typically built in corners. The spider itself usually hides in a tubular silk retreat tucked into a crack or hole nearby.
Outdoors, you’ll find them in gardens, under bark, around fences, and in any structure that offers cover. They’re not burrowing spiders or ground hunters. They build and wait, which is why the locations they choose tend to be quiet and out of the way. If you’re finding one in your house, it’s almost always in a room or corner that doesn’t see much activity.
Climate Limits on Their Range
Temperature plays a major role in where false widows can survive. Lab research on the cupboard spider found that egg and spiderling survival drops sharply at higher temperatures. At sustained day/night cycles of 32/22°C (about 90/72°F), mortality increases significantly, especially for eggs and female spiderlings. Males showed slightly more heat tolerance, and brief heatwave-like exposures were survivable, but prolonged heat above 30°C (86°F) is a serious problem.
This means false widows thrive in mild, temperate climates and struggle in places with extreme summer heat. It also explains their habitat choices: females are under strong pressure to place egg sacs in sheltered spots where temperatures stay below that 30°C threshold. A cool, shaded shed or an interior wall cavity is ideal. This preference for moderate temperatures is part of why they do so well in the British Isles and coastal California, and why they gravitate toward the insulated, stable environments that buildings provide.
When You’re Most Likely to See Them
False widows are present year-round, but your chances of spotting one shift with the seasons. Mature females can be found in any month. Males, however, are most visible in summer and autumn, when they reach maturity and go looking for mates. This is when they leave their webs and wander, which is also when they’re most likely to end up somewhere unexpected, like a shoe or a bed.
Egg sacs are laid from spring through autumn, so reproductive activity spans most of the warmer months. The autumn spike in sightings that the UK experiences every year is a combination of male wandering behavior and spiders seeking shelter as outdoor temperatures drop. If you’re in an area where false widows are established, September through November is when encounters peak.
How to Tell If They’re in Your Area
If you live in southern England, Ireland, coastal California, or anywhere in Western Europe and the Mediterranean basin, noble false widows are either already present or likely to arrive. The rabbit hutch spider and cupboard spider have even broader ranges across northern Europe and Britain. In practice, if you’re in a temperate climate with mild winters and you live near any kind of shipping or trade hub, false widows have probably been introduced to your region.
The clearest sign is finding their webs. Look for tangled, three-dimensional webs in corners of sheds, garages, window frames, and exterior walls, especially on the south-facing side of buildings where warmth accumulates. The spider itself is roughly the size of a large marble (body about 10mm for females), dark brown to black, often with pale markings on the abdomen. If you’re seeing that combination of messy web, sheltered location, and bulbous dark spider, you’re likely looking at a false widow.