Spider Season in North Dakota: What Lives Here and When It Comes Indoors
1 widow or recluse species has verified records in North Dakota. The indoor season, a live range map, and the lookalikes.
Spiders are moving indoors in North Dakota nowSpiders in North Dakota, by the numbers
Verified records, snapshot 2026-09-19 no recordNorth Dakota's western black widow sits below the record threshold with eleven verified records, all in the west, and stays on the list because NDSU Extension documents the species there. Indoors, the September spiders of Fargo and Bismarck are funnel weavers and house spiders.
The one widow or recluse species recorded in North Dakota
Every species below has verified, photograph backed records in North Dakota. The counts come from iNaturalist and measure how often people find and photograph each spider, never how many there are: a species of packrat nests will always look rarer than one of garages.
| Species | Group | Verified records | What to look for |
|---|---|---|---|
| Western black widow Latrodectus hesperus | Widow | 11 | The black widow of the western states. Glossy black with a red hourglass below, webbing in garages, block wall gaps, irrigation boxes and the undersides of patio furniture. |
- Western black widow (11 records): North Dakota State University Extension lists the black widow among spiders found in North Dakota, most often in the western part of the state.
Where each species has been found in North Dakota
Pick a species. The coloured cells are places where somebody photographed one and the identification was confirmed, redrawn as records are added. It thins over roadless country and thickens around towns, because that is where people look.
Coloured cells are verified Latrodectus hesperus records on iNaturalist, brighter where more have been logged. This is where people have found and photographed the species, so it thins out over roadless country and thickens around parks and towns. It is a record map, not a drawn range boundary. See the underlying records.
When spiders come indoors in North Dakota
Indoor sightings in North Dakota pick up around August 10, peak between August 25 and October 5, and fade by October 31. The wanderers are mature male house spiders and funnel weavers searching for females, plus spring hatched spiders that have finally grown large enough to see. The widow spiders follow the same calendar because females are at full size; the busiest month in the North Dakota record is August.
What the chart counts. Records, and a record needs a spider and a person with a camera. Spring spikes in some states are a late April bioblitz. Switch to the effort adjusted view and each month is divided by every research grade observation logged in North Dakota that month, which strips most of that out. Neither view is a population count.
The spiders people photograph as widows
Most spiders reported as a widow or a recluse in North Dakota are one of the species below. The tells are visible from a comfortable distance, and a spider left alone in its corner stays there.
A widow is glossy, round bodied, and hangs upside down in a low tangle web with a red or orange hourglass underneath. A recluse is plain tan with six eyes in three pairs, a darker violin on the front segment, and legs with no bands and no spines. A violin shaped mark on its own is not a recluse: many harmless brown spiders carry one, and it is faint on many real recluses. A bite is never an identification. Skin reactions have dozens of causes, and Poison Control on 1-800-222-1222 will ask about symptoms, never for a species name.
Mistaken for a black widow
False widow
Steatoda grossa
Purplish brown rather than glossy black, with pale markings on top of the abdomen and nothing underneath. The same tangle web in the same corners, which is why it is photographed as a widow more than any other spider.
Triangulate cobweb spider
Steatoda triangulosa
Small, brown, with a row of pale triangles down the abdomen. Lives in the same low corners and window frames a widow would, and turns up indoors far more often.
Common house spider
Parasteatoda tepidariorum
Mottled tan and brown with a rounded abdomen, in messy cobwebs in ceiling corners, under eaves and behind furniture. The most photographed spider in American houses, and an autumn indoor regular.
What to do about a spider bite in North Dakota
Poison Control: 1-800-222-1222, any time, any state.
North Dakota spider season FAQ
The rest of your North Dakota autumn
More Midwest spider season pages
Species lists, record counts and monthly curves are research grade observations from the iNaturalist API, aggregate counts only, snapshot 2026-09-19 with the curves read live in your browser. They measure how often people find and photograph a species, never how many there are, and a species with no record here may still live here. Season windows are drawn from those curves and are climatological typicals. See every record behind this page. For any bite, wash with soap and water and call Poison Control on 1-800-222-1222. National picture: spider season by state.
Hero image: “Adult Female Black Widow” by Shenrich91, CC BY-SA 3.0