Trail Map of San Francisco Bay Area

The Pacific Ocean moderates the temperatures near the shore, bringing cool, moist conditions year-round. The farther you get from the water, the more the weather returns to normal: hot in the summer, mild in spring and fall, and cold in the winter.

Northern California's Mediterranean climate gets moderate rainfall in the winter months (December to February are the wettest) and almost no rainfall the rest of the year. Translation: Nine months of perfect, sunny days for hiking, biking, paddling or anything else that floats your boat. The coast tends to be fogged in during the summer months, but spectacular views open up in the winter, when rainfall washes the skies clean.

Two parallel mountain ranges run north to south through the Bay Area -- The Coast Range on the west and the Diablo Range on the east. Flatlands ring the San Francisco Bay and the broad area between the ranges south of San Francisco forms Silicon Valley. The California Delta empties into the bay from the east.

The Coast Ranges have two distinct regions: the Santa Cruz Mountains south of San Francisco and the Marin Hills north of the Golden Gate Bridge. Both feature abundant redwood forests and a few of the last remaining stands of old-growth redwoods, some of which are up to 2,000 years old. The forests are mesmerizing and the vistas from the hills overlooking the coast are amazing.

The Diablo Range is anchored by Mount Diablo, the massive peak that dominates the East Bay skyline. The terrain is more rugged than the Coast Range and the weather hotter in the summer, but the spring wildflower show in the Diablo Range is among the best in the region. The hills also have abundant evidence of the Ohlone people, who lived there for centuries before Western settlers arrived.

Marin County is the most recreation-rich section of the Bay Area. Top destinations:

Marin Headlands: Rocky heights next to the ocean just west of the Golden Gate Bridge.

Mount Tamalpais State Park: The highest peak in Marin County has some of most popular Bay Area trails, plus camping, lodging and other opportunities.

Point Reyes National Seashore: Simply one of the prettiest places in North America, with abundant opportunities for hiking, biking, camping and paddling.

Big Basin Redwoods State Park: California's first state park, in the Santa Cruz Mountains west of San Jose, has some of the biggest trees on earth; the hiking and camping are unbeatable.

Don Edwards San Francisco Bay National Wildlife Refuge: Birds galore dwell in the shallow waters, and thousands more pass through this major stop on the Pacific Flyway. Flat trails access much of it from areas near Fremont and northern San Jose.

Henry Coe State Park: The Bay Area's only true backcountry destination attracts hardy hikers, equestrians, mountain bikers, backpackers and wildlife watchers. Spring time at Henry Coe, when the wildflowers are in full bloom, is lovely.

Santa Cruz Mountains: Trails zigzag through much of these Coast Range hills, which are excellent for hiking, biking and scenic driving along Highway 35.

Mount Diablo State Park east of Walnut Creek attracts campers, hikers, bikers and nature watchers. Hiking or road-biking from sea level to the summit is a major goal for serious Bay Area outdoorspeople.

Mission Peak Regional Preserve: This peak on the eastern edge of Fremont offers a tough workout and wonderful sky-high views of the Bay Area and the Diablo Range. It's also a major stop along the 28-mile Ohlone Wilderness Regional Trail, a favorite of local backpackers and equestrians.