When the ocean is tempestuous and the sky gunmetal gray, lace up your hiking boots and visit Muir Beach; just 20 minutes from the Golden Gate, it's the launching point for a 5-mile (round-trip) hike that laps up gorgeous views of the great Pacific. Start your journey with a steady climb up Coastal Trail, a wide dirt trail paralleling the ocean. The huff and puff is worth it: After about three-quarters of a mile, the trail crests to a sweeping vista of the coast where the sea appears to go on forever.
Grab classic pub fare at one of the best après spots in Marin, the English countryside-inspired Pelican Inn. Try the Guinness beef stew and a pint of Pelican Pale Ale (made for the inn by Lagunitas Brewing Company). On nice days, spread a blanket on Pelican Inn's huge front lawn.
"Stick to the coastal trail with great views of the ocean. The Green Gulch trail is physically demanding, but there isn't anything really notable to see."
"Bring plenty of blankets, its not uncommon for wind and fog to sweep in during the evenings."
Take a short detour down to Pirate's Cove (best at low tide)—a pocket beach used as a staging area for bootleggers in the 1920s. Then continue on by climbing the wooden stairs and ascending the trail up the headlands where you'll eventually connect to Middle Green Gulch Trail with northern views of Mount Tam. The path descends to Green Gulch Farm Zen Center and winds back alongside a creek to Muir Beach.
From Muir Beach parking lot, cross the boardwalk and go left on the Coastal Trail. Follow the signs to Pirate's Cove. After a few hundred feet go right and uphill at an unmarked intersection (not going on Middle Green Gulch Trail). The spur trail for Pirate's Cove is reached in just over a mile (noted by the "Pacific Coat Trail" sign). Take caution scrambling down. Continue on Coastal Trail and at the next intersection turn left on Coastal Fire Road. In .7 mile turn right on the Coyote Ridge Trail, then after a few hundred feet turn left down the Middle Green Gulch Trail. When you reach Green Gulch, veer left toward the ocean. After going through the second gate, turn left and follow the trail back to Muir Beach.
Finding a cool hiking trail on a hot day can be a challenge in the bay area. Most folks head for forested parks, and that's fine, but when I crave sunshine and ocean breezes, I drive to the coast. If you get an early start, Muir Beach Trailhead can be a perfect destination. Unlike the Tennessee Valley Trailhead, you probably won't have a lot of company, since at Muir Beach most visitors head straight for the beach, and the trails are empty.
From this trailhead you can hike south into Tennessee Valley, or north into Muir Woods or Mount Tam. The trailhead's low elevation means a bit of climbing no matter which direction you choose, but then you get to walk downhill to finish your hike.