San Francisco packs a lot of neighbourhoods into a small footprint, so distances between areas like North Beach, Chinatown and Union Square are often short in a straight line. What complicates things is the terrain, with some streets climbing sharply enough that a route that looks simple on a map can turn into a genuine hill workout.
The flatter areas, like the Embarcadero along the waterfront or the Mission district, offer easier, more relaxed walking, and many visitors mix the two, tackling a hilly stretch for the views and then dropping down to flatter ground to recover.
Fog and wind can roll in quickly, even in summer, changing the walking experience within the same day, so dressing in layers matters more here than the calendar date might suggest.