The best time to visit San Francisco is: the fall. Re: it is sunniest this time of year!
Healthy eating
Sweetgreen – grab a salad/healthy bowl made to order. They provide seasonal options, build your own options.. with bright, yummy ingredients you can’t go wrong for lunch under $15 here!
Golden Era this is vegan “asian fusion” – love the spring rolls app and lemongrass main p.s. they have mango sticky rice!
Juice shops are plentiful in this city – I like grab one at the Embarcadero to start my day.. nothing like ginger + beets in the morning!
For coffee: Blue Bottle = simple menu (great for first thing in the morning) …OR I love taking MUNI out to Sunset Beach. It stops on Judah St. right in front of my favorite coffee spot: Java Beach Cafe. Drink your coffee next to the Pacific ocean!
Activities
A friend introduced me to Yoga to the People and I’ve already gone twice. This is a yoga studio near the 16th street mission BART stop which offers donation-based classes (I give $5-10) many times throughout the day. The studio space is beautiful! They have mats there so just bring yourself (and a friend?)!
For a touristy day in the sun, I recommend a rental bike ($32/day) loop from the Embarcadero along the water (stop at the Palace of Fine Arts to walk around the pond) then across the Golden Gate Bridge into Sausalito (have a picnic/grab lunch). You can catch a ferry with your bike back to either Pier 39 or the Embarcadero (buy your $12.50 tickets onboard).
Spend a day in the park(s) Golden Gate Park & Presidio Park are beautiful and great places for people watching! (I also love Dolores Park & dog watching at Duboce- try the Duboce Park Cafe if you’re in the area for breakfast/lunch!)
Trips
Hiking in Marin County, just across the bay, followed by some beers and games at Bar Bocce in Sausalito or seafood and beach lounging by Stinson Beach
Napa Valley (wine tasting) is a 1-2 hour drive from the city. I recommend booking a tour at Newton Vineyards OR just going for an easy walk-in champagne tasting at Mumm. I recommend Farmstead for dinner afterwards. 
Drive South down the coastline on Highway 1. Stop for Oysters + lobster rolls + Bloody Mary’s at Sam’s Chowder House and beers at Half Moon Bay Brewing Company.
Have a picnic with a Golden Gate view at Baker Beach.
Walk around Sutro Baths.
Art-tourism
SF MOMA is wonderful (go for the food at In Situ for an AMAZING experience.. I also always grab a slice of “Mondrian cake” in the cafe 🙂
Clarion Alley graffiti is always changing and in a cool area (walk up/down Valencia)
Walk up the tile steps on 16th Ave for a beautiful view of the city (and a cool route to the top!)
Grace in the World 