The sky behind the buildings is like a piece of gray cardboard. The street is the same hue, so on the steep slope beyond Van Ness it disappears into the mist. Not a leaf stirs in the tree-tops. San Francisco fog is rolling in, not in dramatic billows but as a sort of creeping erasure,.

No cars. No young men smoking joints on the roof, no yoga ladies, no lively conversation in the gazebo, no squawking parrots. Just a robin two doors down on the rail of a fire escape. It hops a couple of times, then flies away.

Today I will not run my laps because my right foot has gotten sore, and I should perhaps not put too much weight on it. Instead, I will ride my stationary bike — but cautiously. I found two large screws on the floor near it, and can’t figure out exactly where they go, and I fear the thing falling apart beneath me. A trip to the ER for even a minor injury could be catastrophic for us both. At least the aspirin we ordered from Costco arrived the other day.

I just looked up at my window again. I can make out a pillar of the Golden Gate Bridge in the distance, but everything has faded. If I look carefully, I can see the texture of the wet air, tiny droplets suspended almost in a pattern.

A car just passed and its tires hiss as it goes by. On days like this in the city, water does not fall from the sky. It just appears on every surface outside. Perhaps this will burn off by the afternoon, but at the moment, the twilight seems impenetrable.