Bugs in fall in Austin, and what the first cold front sends indoors

When do the first cool nights reach Austin?

By our count, usually around October 1, but it moves around a lot. We went through 30 falls of NOAA overnight lows at Camp Mabry, 1996 to 2025. The first night at 60 F or cooler usually came around October 1. The first one at 50 F usually came around October 19.

When Austin's first cool nights show up

Our count of 30 falls of NOAA overnight lows at Camp Mabry. One dot per fall; the black tick is the typical date.

• First night at 60 F or below
• First night at 50 F or below
• First freeze, 32 F or below

Some years you get it early, and some years late. The first 60-degree night has come as early as September 7 and as late as October 29. And on average, summer hangs on here: normal highs stay above 90 until September 23, the National Weather Service says.

October is also one of Austin's three wettest months, the Weather Service says. So the first cool, wet week of fall is the one you want to watch.

Which bugs show up first after a cool front?

Usually crickets. They swarm every late summer and fall to some degree, and the timing revolves around cool fronts, says Wizzie Brown, Texas A&M's bug expert in Austin. Crickets don't like heat. They lie low in the heat of the day, and the cool fronts of late summer and early fall change that. The big gathering usually lasts four to six weeks.

If they're piling up around your house, Brown says it's probably the lights. Turn off the ones you don't need. Otherwise the crickets can end up inside, and a pile of dead crickets can stink. Our cricket page covers what we do about them.

Later in fall, you may find tiny specks on your windowsills. They may be hackberry psyllids. Texas A&M says those get inside and collect on windowsills, and they typically show up each fall as it gets cooler. They're harmless, and the best fix is probably just to vacuum them up.

You may see Asian lady beetles, too. They're a classic fall invader. A 2005 study found they fly to buildings in fall once it's warmer than about 70 F, with flights peaking between 2 and 4 in the afternoon.

Why are spiders, scorpions and millipedes inside after a fall rain?

Rain plus cooler weather can drive them in. That's what Brown and Molly Keck, Texas A&M's bug expert in Bexar County, said in 2017 about spiders, scorpions and millipedes. If you're finding scorpions, start with our scorpion guide or scorpion control.

Millipedes live in damp spots under mulch, leaves and rocks, or in the soil. When those spots are right by your house, they can draw millipedes in, and now and then one gets inside, the University of Kentucky's bug experts say. You may see big gatherings after heavy rain. The ones that get in can't survive, so you'll usually find them dead in piles. Sweep them up.

Spiders are trickier, and the FAQ below gets into the myth. If they're bugging you, see spider control.

When do mice start moving in?

When the nights get colder. Where mice live outside, they often move into homes in fall when the nights turn colder, UC IPM in California says. No source gives a set temperature for that. But in our count, Austin's first 50-degree night usually lands around October 19, so by late October, you'll want to start looking.

A mouse can fit through a hole the width of a pencil, about 1/4 inch, the CDC says. Here's where you should look:

• Where pipes and wires come in. The CDC lists these.
• Doors without weather stripping.
• Up at the roof. The CDC says to check among the rafters, gables, eaves and soffits.

Plug small holes with steel wool. It makes a good temporary plug, but it may rust, UC IPM says. For foundation cracks and pipe holes, it suggests metal. Roof rats are their own story, and our roof rat guide covers them. If mice are already inside, that's what our rodent control is for: an active infestation is a separate job from $449, and the sealing is quoted on top once we see the house.

What should you do before the first cold front?

Seal up, and do it early. Texas A&M says fall is a good time to winterize your house so bugs don't get a way in. In our count, only 2 of 30 falls had a 60-degree night before mid-September, so that's a good target.

Printable checklist

Before the first cold front

Aim for mid-September. Only 2 of our 30 falls had a 60-degree night before then.

By mid-September

• Plug small holes with steel wool. It's a temporary fix and may rust.
• Check where pipes and wires come in.
• Fix screens, and add door sweeps or weather stripping.
• Trim branches off the house and roof.
• Move firewood away from the walls.
• Pull mulch, wood piles and pavers back from the house.

When fronts and rain arrive

• Spread fire ant bait. Fall is a great time, Texas A&M says. Follow the label.
• Turn off outdoor lights you don't need. They're probably why crickets pile up.

After a front

• Vacuum psyllids and sweep up millipedes. Spraying usually isn't worth it.
• Look for mouse droppings and gnaw marks. In most cases, snap traps are a good first step.

Download the printable checklistPDF, one page

If you'd rather watch, Texas A&M's Wizzie Brown walks through the same ideas in this short news clip.

Can you handle bugs in fall yourself, or should you call?

A lot of it is a vacuum and some steel wool. The sealing on the checklist is homeowner work. A few moves just waste your time, though.

Call us when it doesn't stop:

• Scorpions inside more than once. One is a visitor. If you keep finding them, they're getting in somewhere.
• Mouse droppings or fresh gnaw marks. UC IPM says those show where mice are active.
• Crickets or millipedes still pouring in. If it keeps up after you've sealed, there's probably a gap you haven't found.
• You'd rather not deal with it. That's fair, too.

Our recurring plans cover 40+ pests and start at $66 a month. See our services for what's included.

Common questions