Shorter days, cooler temps, fog and mist coming in. That's no reason to pull the covers over your head. Grab your gear and get out the door.

Invite 20 of your best friends and kindle up some fun with a bonfire on San Francisco's Ocean Beach. Bring blankets, guitars, and—for those of you with really lousy voices—bongo drums. S'mores are still in season and so is toasting comrades on the continent's edge. The sky and sea are your amiable hosts and if that weird relative 'fog' shows up, well, that's what the fire is for. Safeway at the Beach has all the supplies you'll need at the end of Aisle 5: firewood $9.99, marshmallows $3.53, six-pack of Hershey's chocolate $3.69, Safeway graham crackers $1.99; total $19.20.

Details: Bring a bucket to put out the fire. Fires only allowed on beach between Lincoln Way and Fulton St. Parking tickets given in parking lot after 10 p.m. Alcohol not allowed.

Safeway, 850 La Playa St. at Fulton St., SF.

What's big, green, and lurking just over the hills from downtown Oakland? It ain't Godzilla. It's Redwood Regional Park with its 150-foot-tall eponymous trees. This East Bay oasis offers hikers, bikers, and even horseback riders a chance to enjoy its 1,836 acres. Tackling the park's rugged trails, you may see wildlife including deer, golden eagles, and a creek full of rainbow trout. Besides the redwoods you'll also encounter groves of eucalyptus, madrone, and coast live oaks. Try the loop below for a taste of the East Bay's wild side.

Directions: Park at Canyon Meadow Staging Area by entering Redwood Gate off of Redwood Rd. Follow Stream Trail for .24 mile and turn left at the bicycle sign for Bridle Trail. Follow for .20 mile to Orchard Trail and turn right. This is a steep .37-mile climb. Turn right at French Trail and follow this 1.42 miles to Fern Trail and go right. This takes you back to Stream Trail, which with a right turn takes you back to your car. Maps are available at the park. For more information click here.

Luke Skywalker never had this much fun. Intermediate and advanced mountain bikers should check out the trails at Purisima Creek Redwoods Open Space Preserve on the Peninsula. You'll descend 1,000 feet on Whittemore Gulch Trail's kick-butt single-track. Negotiating tight turns and racing through a Douglas fir forest will spark memories of the speeder bike–racing scene in Return of the Jedi. No Ewoks, however. The payoff: gorgeous glimpses of Half Moon Bay and, afterwards, a burger and beer next to the fireplace at the Mountain House. Get here now: the trail closes to mountain bikes in the rainy season, usually by late November.

Purisima Creek Details: Park at Purisima parking lot off Skyline Blvd. Follow North Ridge Trail signs. After 3/4 mile, turn left down Whittemore Gulch Trail. Follow Whittemore Gulch Trail down and down about 3 miles. Cross the bridge to the lower parking lot. Take the Purisima Creek trail back up to Highway 35 (Skyline) and take a left back to your car.

Trail closure updates and map

The Mountain House, 13808 Skyline Blvd., Woodside, 650-851-8541.

OPEN VOTING SEASON: Don't forget to vote on Tuesday! And while you're in the voting mood, take a minute to send us your favorite Northern California outdoor activities. Tell us what and where, and why you like it. Write your entry to info@weekendsherpa.com. We'll spotlight our favorites in weeks to come.