WHAT: An autumn beach fling to Fort De Soto and Caladesi Island parks in Florida's Pinellas County, home to Clearwater and St. Petersburg. The area is a relatively inexpensive 2-hour-20-minute plane ride from the D.C. area.

WHY GO: Former University of Maryland professor Stephen P. Leatherman, aka Dr. Beach, named the parks' Gulf of Mexico beaches among America's Top 5 earlier this year. Leatherman (www.drbeach.org) has rated U.S. beaches since 1991. Need more reasons? The kids are back in school, and room rates are at their lowest for the year.

BY THE NUMBERS: In September, the gulf temperature averages 83 degrees; daytime lows and highs are 73 to 89. In October, the water is generally 77 degrees, the air 65 to 84.

WHAT'S THERE: Leatherman's No. 1 choice, Fort De Soto Park's North Beach, is just southwest of St. Petersburg. The park has "something for everyone," says Leatherman, with 1,100 acres of "great fishing, boating, canoeing, kayaking, bird-watching, camping." There are also bike rentals, accessible trails and a snack bar. Free admission; bridge toll 85 cents. Details: 727-582-2267, www.pinellascounty.org (click on "visitor," then "county parks").

Caladesi Island State Park was No. 4 on Leatherman's list (the other three: Ocraroke Island, N.C., and beaches in Kauai and Maui). The park is accessible by ferry (727-734-5263; $8) from Honeymoon Island, just north of Clearwater Beach and west of Dunedin. At Honeymoon, which connects to the mainland, entrance fees are $5 a car. The park boasts uncrowded white sand plus a three-mile nature/history trail, kayak trail, boat rentals, picnic shelters and snack bar. Details: 727-469-5918, www.floridastateparks.org.

GETTING THERE: Round-trip air starts at about $123 from the D.C. area to Tampa, about a 45-minute drive to both beaches.

WHERE TO STAY: Lodging options range from spa resorts and beach hotels to bed-and-breakfasts and condos.

The Sheraton Sand Key Resort (1160 Gulf Blvd., 800-456-7263, www.sheratonsandkey.com) in Clearwater Beach has a spa and fronts 13 acres of gulf sand. Rates from $198 per night double. Grielens Green Gables Bed & Breakfast (1040 Sunset Point Rd., Clearwater, 727-442-8722, www.greengables.us) has three "Old Florida"-style rooms and a cottage apartment. Rates from $115. The Safety Harbor Resort and Spa (105 N. Bayshore Dr., 888-237-8772, www.safetyharborspa.com) in Safety Harbor has spa and fitness space, spring-fed pools, and golf and tennis academies. Rates from $104.

In St. Pete's historic district, Dickens House (335 Eighth Ave. NE, 800-381-2022, www.dickenshouse.com) is a restored 1912 Craftsman with five rooms. Rates from $105. Nearby, the Renaissance Vinoy (501 Fifth Ave. NE, 888-303-4430, www.vinoyrenaissanceresort.com) includes a marina, golf and tennis. Rates from $219.

WHERE TO EAT: In Clearwater Beach, Bobby's Bistro & Wine Bar (447 Mandalay Ave.) has a wine list two feet long and entrees from $10, while the Island Way Grill (20 Island Way) is a magnificent art-glass-filled restaurant with innovative Asian-influenced cuisine (entrees from $9.95). For a more casual meal, go to the nearby Palm Pavilion Grill & Bar (10 Bay Esplanade), which is right on the sand and has good grouper sandwiches ($7.99).

Columbia serves Cuban- and Spanish-influenced cuisine in Clearwater Beach (1241 Gulf Blvd.) and on the Pier in St. Pete; entrees from $16.95. St. Pete is also home to the original Bonefish Grill (5901 Fourth St.), renowned for its cedar-plank salmon with chorizo; entrees from $13.80. Nearby, Redwoods (247 Central Ave.) serves an ambitious modern-American menu in a white-tablecloth setting; entrees from $22.

OTHER ATTRACTIONS:

* The Clearwater Marine Aquarium (249 Windward Passage, 727-441-1790, www.cmaquarium.org; $9) has exhibits on the animals it rescues and rehabilitates -- particularly sea turtles, dolphins and river otters.

* The Florida Botanical Gardens (12175 125th St. N., Largo, 727-582-2200, www.flbg.org; free) features palm trees, roses, topiary and native species.

* The Salvador Dali Museum (1003 Third St. S., 727-823-3767, www.salvadordalimuseum.org; $14) in St. Pete has one of the world's most comprehensive collection of the artist's works.

INFORMATION: St. Petersburg/Clearwater Area Convention & Visitors Bureau, 877-352-3224, www.floridasbeach.com.

-- Ellen Ryan

Stephen P. Leatherman, known as "Dr. Beach," stands on Florida's North Beach.