People are being warned of thousands of sex-crazed spiders set to invade our homes at the end of the month, with the arrival of autumn signalling the start of spider mating season. This is everything you need to know about spider mating season, and some handy tips to keep the eight-legged creepy crawlies at bay when the time comes. When is spider mating season? Spiders usually start to come out in early September, with their presence noticeable in homes until around mid-October. Money, cellar and lace web spiders will likely be seen more frequently over the coming weeks, as well as house spiders, which is one of the UK’s biggest spiders.