Why Are There So Many Spiders in the House This Time of Year?

Spiders in the House: Causes, Identification, and Prevention

If you’ve noticed more spiders in the house lately, you’re not imagining it. As Southland’s temperatures drop, spiders that spent the warmer months outdoors start looking for somewhere warmer, drier, and safer to wait out winter, and your home ticks every box. Understanding why spiders in the house become more common in autumn and winter, which species you’re likely dealing with, and what actually keeps them out can save you a lot of unnecessary stress (and a few unpleasant surprises behind the curtains).

Why Spiders in the House Increase When It Gets Cold

Spiders are cold-blooded, so they can’t regulate their own body temperature. When outdoor temperatures fall, their food sources (flies, moths, and other insects) become scarcer, and staying outside becomes a losing proposition. Homes offer three things spiders need to survive: shelter from wind and frost, a steady supply of insects drawn in by light and warmth, and quiet, undisturbed corners to build a web or hide.

This is why spiders in the house tend to spike noticeably from late autumn through winter in Invercargill and across Southland. It’s not that spider numbers have suddenly exploded outdoors; it’s that the ones already living around your property are relocating, often through gaps you didn’t know existed.

Common House Spiders in Southland

Not every spider you find indoors is cause for concern. Southland homes typically host a mix of the following:

  • Grey house spiders are the most common visitors, often found in webs in corners, window frames, and garages. They’re harmless to humans but can multiply quickly if left undisturbed.
  • Daddy long-legs are frequent basement and ceiling dwellers. Despite the myths, they pose no real threat to people.
  • White-tailed spiders are more of a concern, as their bite can cause a painful, slow-healing wound in some people. They’re hunters rather than web-builders, so they’re often found roaming at night rather than sitting in a web.
  • Black cobweb spiders favour cluttered, undisturbed areas like sheds, woodpiles, and under furniture.

If you’re regularly finding spiders in the house and you’re unsure which species you’re dealing with, it’s worth getting a professional opinion rather than guessing; some species warrant more caution than others.

What Attracts Spiders Inside

A few conditions make a home particularly appealing to spiders looking for a winter refuge:

  • Gaps around doors, windows, and foundations give spiders (and the insects they feed on) easy access. Even small cracks around pipes, vents, and cladding are enough for smaller species to squeeze through.
  • Outdoor lighting near entry points attracts flying insects at night, which in turn attracts spiders looking for an easy meal right at your doorstep.
  • Clutter in garages, sheds, and under beds creates undisturbed spaces where spiders can build webs without being bothered.
  • Firewood stacked against the house is one of the most common ways spiders (and other pests) end up indoors, since it’s rarely moved and offers excellent shelter.
  • Damp, dark areas such as under sinks, in roof cavities, and in subfloor spaces are ideal breeding grounds, particularly for species that prefer humidity.

How to Reduce Spiders in the House

You won’t eliminate spiders entirely — they’re a normal part of the outdoor ecosystem, and many are actually beneficial for keeping insect numbers down, but there’s a lot you can do to stop them making themselves at home indoors.

Seal obvious gaps around windows, doors, and where pipes or cables enter the house. This single step does more to reduce spiders in the house than almost anything else, because it also cuts off the insects they hunt.

Vacuum regularly in corners, behind furniture, and along skirting boards to remove webs, egg sacs, and juvenile spiders before they establish themselves.

Store firewood away from the house, ideally raised off the ground and at least a few metres from any entry point.

Reduce outdoor lighting near doors and windows, or switch to yellow-toned bulbs, which are less attractive to insects.

Declutter storage areas like garages and sheds so there are fewer undisturbed spots for webs to form.

Address damp issues in subfloors, roof cavities, and bathrooms, since moisture problems tend to attract both insects and the spiders that feed on them.

When to Call in a Professional

If DIY steps aren’t keeping pace with the number of spiders in the house, or if you’re finding white-tailed spiders regularly, a targeted treatment is usually the faster and more reliable option. Professional pest control treats the areas spiders actually nest and travel through, such as wall cavities, eaves, subfloors, and entry points, rather than just the webs you can see. This breaks the cycle instead of temporarily clearing out one generation of spiders while the next batch moves in behind them.

At Nexus Property Services, our Southland team treats homes for spiders and other common pests using methods that are safe for family and pets once dry, with a focus on the entry points and nesting areas most DIY treatments miss. If spiders in the house have become a recurring headache this season, get in touch, and we’ll take care of it properly — so you’re not doing this again next winter.