Why would a flock of geese have been flying southeast over a Northern California city?

Maybe crops SE of you are starting to produce and the geese are looking forward to some farm-to-table dining?

Seriously, I’ve seen them do that in Maryland, going to soy and corn fields.

Heat. Trying to get ahead (or behind) prevailing winds.

Ah. Out for dinner. Pretty loud and sociable about it, too.

Enviable.

And I didn’t think about wind direction. Wind was not noticeable where I was, and temperature was in the mid-seventies. But geese probably know more about wind and weather than I do.

My guess is that since you spotted them in the evening they are returning from a day of foraging to an habitual spot for spending the night. This is particularly likely if the birds were low in the sky. Were they headed in the direction of the marshlands or bay near you? Odds are, if you want to invest the effort, you can track em down through watching for them nightly.

They were most likely looking for a body of water to shelter for the night. We get them here at our reservoir in Lafayette for the evening, often flying east to west.

They may have been headed to Anderson Lake or Calero Reservoir.

Probably the same reason they do it here. There is a park nearby where they graze on grass during the day, then fly NW to a small lake. Tomorrow they’ll do it again…