That chill you feel outside after dark may be more than the weather. Four haunted houses are opening this weekend, promising to send shivers down the spines of all who venture out. Here's a preview.

* HAUNTED CAVERN

* Address: Ruby Falls, 1720 S. Scenic Highway, Lookout Mountain.

* Setup: Wyrmwood Asylum, a long-abandoned sanitarium for the criminally insane located in the dark recesses of a cave 260 feet underground.

* First peek: 8 p.m. Saturday. Continues Fridays and Saturdays through Oct. 10, then Thursday through Sunday, Oct. 15-Nov. 1. Ticket sales start at 7:30 each night. Closing times generally 11 p.m. Fridays and Saturdays, 10 p.m. Thursdays and Sundays, but can be later to accommodate crowds.

* Admission: $20 online, $22 at door (including tax). Not recommended for children under 10.

* Phone: 821-2544.

* Web site: www.hauntedcavern.com.

* HAUNTED CARNIVAL

* Address: Sir Goony's Family Fun Center, 5918 Brainerd Road.

* Setup: A war-weary medic returns from the Civil War to find his wife and child massacred by outlaw Union soldiers. He forms a traveling sideshow, Dr. Knight's Carnival of the Unknown, to search for the killers and feed his hunger for revenge through their gruesome deaths.

* First peek: 7 tonight and Saturday. Continues Oct. 2-3, 9-10, 16-17, 23-25 and 28-31.

* Admission: $20 adults, $12 children under 12. Includes haunted golf, go-kart rides and other activities.

* Phone: 892-5922.

* Web site: www.sirgoonys.com.

* CLOWN TOWN

* Address: Eastgate Town Center behind Applebee's, 5600 Brainerd Road.

* Setup: The clowns have been locked away since 2006. Now they're back with a vengeance.

* First peek: 8 p.m. Thursday. Continues Oct. 2-4, 8-11, 15-18 and 22-31; open until at least midnight Fridays and Saturdays.

* Admission: $15. Children 12 and under must be accompanied by an adult.

* Web site: www.darksidewrestling.net.

* HAUNTED BARN

* Address: 5107 McDonald Road, McDonald, Tenn. Directions posted online.

* Setup: This two-story, country barn, which includes 16 rooms and a maze, has been restaged with new special effects and characters. Wait your turn by the bonfire or with a stroll through the Haunted Graveyard.

* First peek: 7:30-midnight tonight and Saturday; ticket sales start at 7 p.m. Continues each Friday and Saturday through Halloween,

* Admission: $15. Not recommended for children under 12.

* Phone: 423-396-9790.

* Web site: www.thehauntedbarnchattanooga.com.

* HAUNTED HOUSE ON BROAD STREET

* Address: 2201 Broad St.

* Setup: Debut of 20 rooms of horror in an actual, 100-year-old mortuary.

* First peek: 7 p.m. Thursday. Open till midnight every Thursday-Sunday in October. Open Nov. 1 for all-ages visits.

* Admission: $20. Appropriate for ages 16 and up.

* Web site: www.myspace.com/hauntedhouseonbroadstreet.