Madrid to San Francisco (MAD–SFO) — Airlines, Schedules & Connections

Spain is part of the US Visa Waiver Program. Spanish passport holders can enter the US for tourism or business for up to 90 days with an approved ESTA (Electronic System for Travel Authorization). Apply at esta.cbp.dhs.gov at least 72 hours before departure. The fee is USD 21. The ESTA is valid for 2 years or until your passport expires, whichever comes first. It covers multiple entries.

Your passport must be machine-readable and, for VWP travel, must be an ePassport (the kind with the chip symbol on the cover). Spanish passports issued after 2006 meet this requirement. The 90-day ESTA stay cannot be extended and cannot be changed to another visa status from inside the US. If you need more than 90 days, apply for a B-1/B-2 visa at the US Embassy in Madrid.

US border officers have wide discretion. Have your return flight, hotel address, and a general itinerary ready. ESTA approval does not guarantee entry. The CBP officer makes the final decision at the port of entry. Global Entry (USD 100, 5-year membership) speeds up arrivals significantly at US airports if you travel frequently.

Metro Line 8 runs from Nuevos Ministerios (central Madrid) to T1/T2/T3 in 12–15 minutes (€6, including the airport supplement). T4 requires an additional free shuttle from T2; add 10 minutes. The Cercanías commuter train (Line C-1) reaches T4 from Atocha station in 25 minutes (€2.60, no supplement).Taxis have a fixed fare of €30 from central Madrid zones. The ride is typically 20–35 minutes depending on traffic. Avenida de América bus hub serves several airport bus routes (€5).

BART from SFO station (free AirTrain from any terminal to the station) to downtown San Francisco takes 30–40 minutes ($10.45 to Embarcadero). Traffic on 101 can make taxis and ride-hails much slower during peak hours; BART skips all of that. BART also reaches Oakland, Berkeley, and Millbrae for Caltrain connections.Ride-hails from SFO use a dedicated garage pickup area; follow signs. Taxis are metered; downtown SF costs $40–60. Caltrain to the Peninsula (Mountain View, Palo Alto, San Jose) requires taking BART to Millbrae station for the transfer. Rental cars are at a consolidated facility accessible by AirTrain.

Coastal fog dominates the climate pattern. The thick marine layer ("Karl the Fog") rolls into SFO from the Pacific regularly in summer (June–September), causing significant low-visibility delays even on days that appear sunny inland. Morning fog burns off by afternoon most days, but persistent IFR conditions can last all day. This is the primary flight disruption risk at SFO.

Temperatures are mild year-round (10–20°C) with little seasonal variation. Winters bring rain (December–March) and occasional atmospheric river events that cause brief but intense flooding on the 101. Summers are cool. Pack a light jacket year-round. Wind off the bay affects small aircraft approach paths.