Spas with hot tub

Adults-only hot springs resort on Miracle Hill in Desert Hot Springs with private mineral tubs, a Finnish sauna, salt room and 35 spa treatments.

Hotel spa inside Dua Miami, Autograph Collection in Brickell, open daily 9am-6pm, with sauna, steam room, cold plunge and couples massage rooms.

Hotel spa inside Florence's Four Seasons, with a walled garden pool, whirlpool, sauna, steam room and couples suite, open to day-pass guests.

A Korean jjimjilbang-style spa in Palisades Park, NJ, with ten heated sauna rooms, hot tubs, cold plunge and a $69 day pass, open daily 9am to 2am.

A 24-hour Korean bathhouse and sauna complex in Niles near Chicago, with 11 heat rooms, hot and cold pools, and a $45 day pass covering walk-in access.

Hotel spa on the lower level of the Fairmont Chicago, open to guests for massages, facials and a couples suite with an infinity-edge soaking tub.

Sante Spa is the adults-only resort spa at the Riviera Palm Springs, with 18 treatment rooms, a Watsu pool, steam room and validated valet parking.

Soft Handz is an adults-only day spa near Minneapolis/St. Paul with sauna, steam room, jacuzzi and cold plunge, open to walk-ins for a $50 day pass.

A 38,000-square-foot resort spa at JW Marriott Desert Springs in Palm Desert offers day passes, saunas, a saltwater lap pool and couples suites.

Six-room hotel spa at Hacienda del Sol in Tucson, open daily 9-6, taking both resort guests and local walk-ins for massages, facials and body treatments.

Hotel spa at the Catamaran Resort in Pacific Beach, San Diego, with a bay-view hot tub, pool and restaurant, open to hotel guests only.

A resort spa inside the Iberostar Waves Tucán in Playacar offering sauna, Turkish bath and jet-pool treatments, open to day-pass visitors 16 and up.

Adults-only hotel spa inside La Concha Resort in Condado, San Juan, offering couples massages and a small treatment menu for guests 18 and up.