SFO

San Francisco International runs one of the tightest scheduled airfields in the country, and it gets away with it exactly as long as the weather cooperates. When the marine fog rolls in — most reliably in the July-August afternoon window, but possible any month — SFO downshifts from two-runway to single-runway ops, which cuts arrival capacity roughly in half. The visible symptom is inbound flights holding over Sacramento; the invisible symptom is your outbound departure creeping later as gate turns cascade.

Terminal 1 (the Harvey Milk Terminal, mostly domestic) is fundamentally different from International Terminal (SkyTeam/Star Alliance/oneworld internationals). Domestic morning peak is 6-8 AM; International's peak is 10 PM-1 AM for Asian and Australian departures. If you have flexibility, midday at International is one of the quietest security experiences at any major US hub.

The unique SFO pattern: a 3-5 PM Silicon Valley tech-worker peak that's shorter and sharper than most US-hub peaks. It's driven by companies that let employees leave early for weekend travel. If you're flying out mid-week, that window is worth avoiding; if you're flying mid-weekend, it's basically gone.

BART directly connects to the International Terminal, and the fare from downtown SF is under $12 — cheaper than parking for a single day. Even during Bay Area rush hour, BART is faster than a taxi via US-101, and reliable in a way that ride-shares in San Francisco simply are not. This is the highest-leverage under-used transit connection at any West Coast airport.