Why Does It Seem Like Black Widows Are Everywhere in Utah Right Now?

Seven black widows around one Murray home in a week. Others showing up in garages, yards and porches across the Wasatch Front.

Utah homeowners have been talking about black widows a lot lately, with some saying they’re seeing more than they remember in previous years.

But are there actually more of them?

We couldn’t find evidence showing that Utah’s black widow population has increased in 2026. What we did find is that fall is exactly when Utah residents are more likely to encounter spiders.

Black widows also have a few behaviors that make them particularly easy to overlook until this time of year.

So here’s what we actually know about why black widows seem to be showing up everywhere right now.

Fall is spider season in Utah

Fall is when Utah residents are most likely to encounter spiders, according to Utah State University. Many have reached maturity by this point in the year, while mating and egg-laying can also increase activity.

That doesn’t prove there are more black widows in Utah this year. It does help explain the timing.

The western black widow spider (Latrodectus hesperus) is found throughout Utah. Are black widows nocturnal? Yes. They hide during the day and are typically in their webs at night, which means they can be present around a property without being particularly noticeable during the day.

Black widow webs can provide another clue. Unlike the symmetrical webs people often associate with spiders, black widows build irregular three-dimensional cobwebs with specialized prey-catching threads.

Where black widows show up around Utah homes

Around Utah homes, black widows are commonly found in dark, undisturbed areas such as garages, window wells, wood piles, foundations, sheds, irrigation and water-meter boxes. Think stored materials that haven’t moved in a while.

These are protected areas where a web can remain relatively undisturbed.

Black widows are sit-and-wait predators, they work smarter, not harder. Instead of roaming around looking for insects, females build irregular webs with sticky trap threads that capture prey.

Researchers studying western black widows found that food-restricted females changed those webs, producing more prey-catching trap threads than well-fed spiders.

That’s also one reason insect activity around a property matters. USU recommends reducing the insects spiders feed on as part of black widow management.

Adult western black widow found in Salt Lake County.

But an adult female isn’t the only black widow you might find.

Not every black widow looks like the one you’re expecting

So what does a black widow look like? An adult female western black widow has a shiny black body, a large rounded abdomen and is roughly 1/2 inch long in body length, not including legs. The familiar red hourglass ⌛ is on the underside of the abdomen.

But that description applies to the mature female.

Juvenile western black widows can have white, orange and red markings before becoming darker as they mature. Males are much smaller and lighter-colored.

That caused some confusion in Salt Lake this week when a homeowner posted a spider online asking:

“Not a black widow right?”

The spider appeared to be a juvenile western black widow.

Do all black widows have red spots or a perfect red hourglass? No. On adult females, the marking can appear as a complete hourglass, two separate triangles, an incomplete marking or a very faint red coloration. In rare cases, the red can be nearly or completely absent.

So, no, not all black widows look the same. They’re not all female, either.

Are male black widow spiders venomous? Yes. Males do possess venom, which they use to subdue prey, but their fangs are too small to break human skin. Medically significant black widow bites are associated with adult females

Juvenile western black widows can look considerably different from adult females.

If you find a black widow

Black widows aren’t considered aggressive, although females can defend their egg sacs.

Be careful when moving firewood, opening irrigation boxes, cleaning garages or handling stored materials in areas where you’ve found webs. Gloves are a good idea, and don’t reach blindly into protected spaces.

Can you survive a black widow spider bite? Yes. Most people recover, although a bite can cause significant symptoms such as pain, muscle cramping, sweating and elevated blood pressure and severe cases may require hospital treatment Utah Poison Control says recovery after black widow envenomation is expected to be complete within a few days.

For a suspected bite, contact the Utah Poison Control Center at 1-800-222-1222 for guidance.

For the property itself, pay attention to how many you’re finding and where.

One widow in a wood pile is different from repeatedly finding adult females, egg sacs or established webs around a garage, window wells or areas your family regularly uses.

Removing webs, reducing clutter, sealing gaps and reducing the insects spiders feed on can all help.

If you’re not sure what kind of spider you found, take a clear photo before trying to identify it from memory.

So, are there more black widows in Utah this year?

We don’t know.

The reports we’ve seen from Murray, Salt Lake and other parts of the Wasatch Front are individual homeowner observations. They don’t establish a population increase.

What we do know is that fall is already Utah’s peak season for spider encounters, western black widows are established throughout the state, they’re primarily active at night and they commonly build webs in protected areas around homes.

Those factors can help explain why homeowners may be noticing them right now without claiming Utah is experiencing a black widow boom.

And if you’re seeing them repeatedly around your own property, that’s something we can actually help with.

Spider control in Salt Lake County

TAGZ offers one-time spider control from $179 and year-round pest protection starting at less than $2/day.

No long-term contracts. Low-tox options available. Text to book. Text to cancel.

Text or call TAGZ at (801) 610-6965.

Sources

Utah State University Extension: Spider Encounters Most Likely in the Fall
https://extension.usu.edu/archive/spider-encounters-most-likely-in-the-fall
Utah-specific information on fall spider activity and seasonal spider encounters.

Utah State University Extension: Black Widow Spider
https://extension.usu.edu/planthealth/ipm/notes_nuisance/black-widow
Utah-specific information on western black widow identification, juveniles, males, common hiding areas, nighttime activity and management recommendations.

Utah Poison Control Center: Black Widow Spider Envenomation
https://poisoncontrol.utah.edu/news/2023/09/case-files-black-widow-spider-envenomation
Utah medical guidance on black widow bites, symptoms, treatment and recovery.

Utah Poison Control Center: Bites and Stings Basics
https://poisoncontrol.utah.edu/news/2022/03/bites-and-stings-basics
Guidance on spider bites, venom exposure and when to contact Poison Control.

Behavioral Ecology: Effects of Resource Availability on the Web Structure of Female Western Black Widows
https://academic.oup.com/beheco/article/33/6/1170/6700673
Peer-reviewed research on western black widow web structure and changes associated with food availability.

Local Reddit discussions are referenced only as anecdotal examples of what Utah homeowners are reporting in 2026. They are not evidence of an increase in Utah’s black widow population.