In San Juan’s hot, arid climate, the vineyards thrive on water from 3,200-hectare Dique Ullum, 18 kilometers west of town via RP 60; it’s also the place where sanjuaninos go to beat the heat by swimming, sailing, windsurfing, and fishing. From the bus terminal, take bus No. 29; for schedules, contact Empresa Ullum (tel. 0264/4221910).

If the heat relents, hike from the dam outlet to the top of 1,800-meter Cerro Tres Marías. This waterless walk traces the crest of the southwest-trending Serranía de Marquesado and takes two hours one-way. The conspicuous zigzag trail begins at the Stations of the Cross; carry plenty of liquids and high-energy snacks.

Water sports are the primary attraction on the crescent of sandy beaches stretching from Muelle Storni in the north almost to Punta Cuevas in the south. In these sheltered waters, hazards like rip currents are nonexistent, but at low tide the water retreats hundreds of meters on the gently sloping beach.

The road may be paved and fuel much easier to come by than in the early days of peninsular travel, but Baja California remains a classic route for travelers who enjoy the thrill of a long road trip. All you need is ample time, a reliable vehicle, and an ability to cope with unpredictable situations.

Travelers with a week or more can experience the many dimensions of the lower Baja peninsula by making a circular route around the Cape Region via paved highways Mexico 1 and Mexico 19. Extending a total distance of approximately 564 kilometers (350 mi), this route takes visitors along the lower slopes of the Sierra de la Laguna, through the sierra’s former mining towns, across the plains of La Paz, and along the coastlines of the East and West Capes as well as the Corridor between San José del Cabo and Cabo San Lucas.

Look for Skydive El Sol (tel. 624/129-7173, www.skydiveelsol.com, open daily year-round), a relative newcomer to Cabo San Lucas, near Club Cascadas on Playa El Médano, where the going rate is US$200 for a tandem jump that includes one minute of freefall time.

Plan on a two-hour outing, from start to finish. For an additional US$90, you can return home with a DVD of the entire experience. Skydive El Sol needs at least two jumpers to book a trip.

The gently curving shore of Bahía de Palmas, stretching 32 kilometers (20 mi) from Punta Pescadero south to Punta Arenas, began its commercial life in the 1960s as a fishing resort accessible only by yacht or private plane. Now that the Transpeninsular Highway swerves to within a couple miles of the bay, it has become a full-fledged fishing and windsurfing mecca.

Most dive and kayak outfitters also run snorkel tours. Less expensive trips visit the beaches along Peninsula Pichilingue; the more expensive ones go to the islands for the day. For example, Buceo Carey offers snorkeling trips for US$65 to Playa Encantada and the sea lion colony.

Baja Diving and Service at the Cantamar does local snorkel trips for US$50.

A new official road sign points the way to Playa Los Cerritos at Km 64 (12.8 km/8 mi south of Todos Santos). From the turn, follow a good dirt road 2.7 kilometers (1.7 mi) southwest until you reach the sandy parking area.

Sheltered by Punta Pescadero at its north end, the beach is usually safe for swimming. Throw on a pair of goggles and you may even catch a glimpse of a spotted eagle ray gliding by just offshore. Boogie boarding is another popular activity.

Parasailing (paracaídas in Spanish) is that classic beach thrill ride in which you don a parachute and are pulled behind a boat to a dizzying height. If you do it only once, do it in Cancún for views of the endless white beaches and impossibly turquoise sea. You can choose a traditional one-person ride (with takeoff from the shore) or a two-person ride, in which you sit in a small raft and take off from the boat or the water.

Ikarus Kiteboarding School (tel. 984/803-3490, www.kiteboardmexico.com) is based in Playa del Carmen but opened a new kiteboarding camp at Isla Blanca, a huge saltwater lagoon north of Cancún. Conditions for learning to kiteboard don’t get much better than this: steady wind, kilometers of flat water with few boats or other obstacles, and the water’s never more than waist deep.