Jet Lag Flying From the US West Coast to India (and Back): Why It Takes a Week

Why this route is hard

India is 13.5 hours ahead of Los Angeles and San Francisco in winter and 12.5 in summer. No route from the US comes closer to turning the body clock upside down. Because a clock can only be moved so far in one direction, the Jet Lag Calculator resolves it by the shortest path: going out is a 10.5 hour delay in winter and 11.5 in summer, and coming home is the same hours as an advance.

At this size the direction is not obvious to the body either. Circadian research notes that shifts beyond about nine hours can go either way, and some people's rhythms split, with some advancing while others delay, which is part of why re-entrainment on this route is slow and uneven. The calculator commits to the delay on the outbound leg because it is the direction the clock drifts on its own and the one that finishes soonest: about 8 days in winter and 9 in summer. The return, an 11 hour advance, is rated at 11 to 12 days, the longest of any route on this site.

The flights are long in both directions. Nonstops from San Francisco to Delhi, Mumbai and Bengaluru run 16 to 17 hours and land between late evening and the small hours. Connections through the Gulf add a layover that almost always falls in the middle of your biological night and land in India around 2 to 4 AM. Coming home, nonstops leave India in the small hours and land on the West Coast in the early morning of the same calendar day, so you arrive at what feels like late afternoon with a whole day ahead.

Two things make the route manageable. Prep nights shift you two hours before you board in either direction. And on the way out, the delay means an early first night is correct rather than a failure, which is the opposite of what most travellers try to do.

Flying out

Enter your route in the calculator and it produces a plan in three parts: prep nights before you fly, the flight, and arrival days. Here is what it does for Los Angeles to Delhi with two prep days, a usual bedtime of 10:30 PM and a winter departure. Mumbai and Bengaluru share Delhi's time zone, so the plan is the same for all three.

Prep nights. Each prep night moves bedtime an hour later: 11:30 PM two nights before, 12:30 AM the night before, with wake time sliding later to match. Bright light in the evening pushes the clock later; a dim first hour after waking stops the morning from pulling it back. Two prep nights take two hours off the 10.5 you need.

The flight. No scheduled sleep window. On a 16 hour flight the calculator's advice is to sleep during the part that overlaps your normal night at home, then stay awake and in cabin light for the rest, without alcohol. If you can add an hour of sleep a night in the week before, the Sleep Banking Calculator shows what that reserve is worth on a flight this long.

First night in India. The plan's first sleep window runs 3:45 PM to 11:45 PM local time. That looks strange and it is the honest answer: 3:45 PM in Delhi is 2:15 AM in Los Angeles, and after two prep nights that is when your body is ready to sleep. In practice most flights land late at night, so night one is usually split: a short sleep on landing until morning, daylight late in the morning, and then the plan's afternoon bedtime the next day. The light window on the plan runs from about 12:45 PM to 3:15 PM, the hours before that early bedtime; the hour after waking, close to midnight, is the avoid-light window, which is easy to honour.

Days two to five. Bedtime moves about 1 hour 45 minutes later each night: 5:30 PM on night two, 7:15 PM on night three, 9 PM on night four, and your usual 10:30 PM on night five. Afternoon and evening light, a dim first hour awake and no long naps keep the delay moving. The plan reaches Indian time in 7 days in winter and 8 in summer.

If you fly without prep nights, or you are reading this on arrival, switch the calculator to "I already landed". The first sleep window then runs 1:45 PM to 9:45 PM local, with a light window from late morning, and the same 1 hour 45 minute steps after that, reaching local time in 6 days.

Open the outbound plan for the West Coast to India. Already there? Start from tonight.

Flying home

India to Los Angeles is a 10.5 hour advance in winter and 11.5 in summer, and it is the hardest leg of any US route. The calculator estimates 11 days of recovery in winter and 12 in summer. Advancing fights the clock's natural drift, so it runs at about a day per zone, and there are more zones here than anywhere else.

The flight timing does not help. Nonstops leave India in the small hours and land on the West Coast in the early morning of the same date, after 16 hours in the air. Your body reads the landing as late afternoon, so the first day at home is long and the first night starts very late.

The return plan with two prep nights moves bedtime an hour earlier each night before you fly: 9:30 PM then 8:30 PM Indian time, with bright light after waking and a dim two hours before bed. Do these two nights. On this leg they are the difference between an 11 hour shift and a 9 hour one, and the calculator drops a full day from the arrival plan for each.

On the night you land, the sleep window runs 5:30 AM to 1:30 PM Los Angeles time, which is the body's 7 PM Indian bedtime after the prep shift. Expect to be awake through the first evening and most of the night; keep the lights low from about 3:30 AM, sleep when the window opens, and get outside in the light window from 1:30 PM to 3 PM after waking. Bedtime then moves about 90 minutes earlier each night: 4 AM on night two, 2:30 AM on night three, 1 AM, 11:30 PM, and your usual 10:30 PM on night six. The plan reaches Los Angeles time in 8 days in winter and 9 in summer.

The symptoms to expect are the classic advance ones: unable to fall asleep, unable to wake, and an afternoon collapse around what your body still thinks is 3 AM. If you must nap, keep it under 30 minutes and before 3 PM. A long afternoon sleep on day two or three will push the whole plan back.

Open the return plan for India to the West Coast, or start from tonight if you are already home.

Short trips

Under three nights, do not adapt. An 11 hour shift takes most of a week, and a trip that short would end while your clock is halfway across, leaving you to advance the whole distance back. Stay near West Coast time: on a Los Angeles clock, India's morning is your evening and India's late afternoon is your early morning, so a schedule that runs from mid-afternoon into the night local time fits a home-time body well.

For four to six nights, adapt going out, but plan the return before you leave. The last two nights in India are the return leg's prep nights; move bedtime an hour earlier on each, and the flight home starts from a 9 hour shift instead of 11.

For a week or more, run both plans in full. The outbound plan reaches Indian time by about day seven, so a two-week trip gives you a full week adapted, and the prep nights before the return still matter as much as they do on a short one.

Light, melatonin and caffeine

The three levers point in opposite directions on the two legs, which is what makes this route confusing to read about.

Light. Going out, the clock needs to move later: seek light in the afternoon and evening, keep the first hour after waking dim, and avoid a bright early-morning start. Coming home, it flips: bright light in the hour or two after waking and dim light in the two hours before bed. India's daylight is strong and the West Coast's afternoon light is reliable, so the outdoor option exists at both ends.

Melatonin. The Cochrane review by Herxheimer and Petrie found the clearest benefit on eastward trips of five or more time zones, with melatonin taken close to the target bedtime at the destination; that is the return leg here. For westward travel the evidence is weaker but still favourable for sleep onset, with the westward studies taking it shortly before the desired sleep time. The doses studied ran from 0.5 to 5 mg, with the low end doing as well as the high. Whether any of that suits you is a question for your doctor or pharmacist, particularly on a route this long. The Melatonin Timing Calculator shows the timing the studies used for each direction.

Caffeine. Going out, the first-night bedtime is mid-afternoon, so the caffeine cutoff on the arrival day is in the morning: with a 3:45 PM bedtime, the Caffeine Cutoff Calculator puts the last coffee at about 7:15 AM local, which for most arrivals means none at all that day. As bedtime moves later over the following nights the cutoff moves with it, reaching early afternoon by night four. Coming home, the first night starts at 5:30 AM, so coffee on the first evening is fine and the cutoff sits around 9 PM, moving earlier each night as the plan advances. On both legs, a week of short nights builds a debt the Sleep Debt Calculator can size, and it is cleared faster by earlier bedtimes than by long lie-ins.

Educational information, not medical advice. Consult a healthcare provider for sleep disorders or before taking any supplement.