Jet lag from San Francisco to London: what to expect

How long does jet lag last from San Francisco to London?

Unaided, eastward shifts settle at around a day per time zone: about 8 days for this one. S6 S7

This plan targets 6 days.

That's what the plan aims at, not a promise — bodies vary.

For this trip that's 2 days sooner than the unaided estimate, on the effort level that fits around a working day.

On night one the plan's bedtime is 01:00, late by London's clock. It holds there for 5 nights, then moves to 23:00 by night 7.

Studies of aircrew point the same way: after large shifts, westward adaptation runs roughly 50% faster than eastward S6 S8. This trip is on the slow side of that.

What does the plan say for a typical San Francisco to London flight?

Departs

12:30 San Francisco time

Lands

07:30 London time +1 day

In the air

about 11h (estimate)

Light, landing day

13:25–14:25 Get outside into bright light

Keep it dim, landing day

22:00–00:00 Avoid bright light before bed

Last caffeine, landing day

17:00

Nap after landing

09:00 Nap when you can lie down, up to 90 min

First night's sleep

01:00–09:00

Eastbound long-hauls tend to land in the morning, so this example lands in London at 07:30, leaving San Francisco at 12:30 the day before, after about 11h in the air.

The flight time is our estimate for a nonstop from the distance, and the trip is set in January. It's the default traveler from the calculator: usually asleep 23:00 to 07:00, no melatonin, Real Life effort.

The plan gives you 95 minutes of sleep on board, from 05:25 to 07:00 London time, ending half an hour before you land. What's left of that night becomes a nap on the ground at 09:00: "Nap when you can lie down, up to 90 min".

The day before you fly, the plan starts with light at 07:00–08:00 San Francisco time. San Francisco's sunrise, about 07:21 in January, comes partway through, so finish it outside.

January days are short in London: about 9 hours of daylight. In January the sun is up in London from about 07:55 to 16:29, so the 13:25 light step on landing day is daylight. Outside is the easy way to get it.

What helps after flying east to London?

Going east, you want light after your body's low point and darkness before it S1. In the first days after a big shift that often means sunglasses in the morning and the early afternoon outside. Why flying east is harder goes through the mechanism.

Melatonin has its best trial results on eastward flights across five or more time zones S5. It's a timing signal, not a sleeping pill: melatonin for jet lag covers when to take it. Check with your doctor first.

And the flight home from London?

London to San Francisco is the same 8 hours the other way, westward. It's the easier direction: about 6 days unaided, and the plan targets 4. Jet lag from London to San Francisco has the details.

More routes from San Francisco

• San Francisco to Zurich
• San Francisco to Tokyo
• San Francisco to Hong Kong
• San Francisco to Delhi