For jet lag US to Australia, the key fact is that Sydney is 14 to 19 hours ahead of the mainland US, but your body clock can treat that as a 5 to 10 hour westward shift, which usually takes about 4 to 7 days to adjust. From Los Angeles in the Australian summer, it's only a 5-hour shift for your body, about the same as flying London to New York.
The plan below uses a home routine of bed at 11:00 PM and up at 7:00 AM. Plug your own times into the jet lag calculator for a custom version.
Free toolJet Lag CalculatorDays to adjust, plus a shift-before-you-fly schedule.How big is the time difference to Sydney?
It depends on the month, because the US and Australia change their clocks in opposite directions. Sydney moves its clocks forward in early October and back in early April, the reverse of the US. Here's the gap for Sydney and Melbourne, with what it means for your body clock in brackets.
| From | Early Nov to early Mar | Mid Mar to early Apr, and Oct | Early Apr to early Oct |
|---|---|---|---|
| Los Angeles | 19 h ahead (acts like 5 h west) | 18 h ahead (6 h west) | 17 h ahead (7 h west) |
| Chicago or Dallas | 17 h ahead (7 h west) | 16 h ahead (8 h west) | 15 h ahead (9 h west) |
| New York | 16 h ahead (8 h west) | 15 h ahead (9 h west) | 14 h ahead (10 h west) |
Brisbane doesn't use daylight saving time, so in the Australian summer it's one hour behind Sydney.
Why it acts like flying west
Being 19 hours ahead puts you at the same clock time as being 5 hours behind, and your body clock tends to take the shorter, later route. It shifts later more easily than earlier, and it doesn't know which way the plane flew. We explain the 12-hour crossover in jet lag from the US to Asia.
Treat this as a rule of thumb, not a guarantee. Researchers describe body clocks sometimes shifting the "wrong" way after very long flights, and light at the wrong time makes that more likely. It's least predictable from the East Coast in the Australian winter, when 14 hours ahead and 10 hours behind are close to an even split.
At the calculator's rule of about 1.5 hours a day when shifting later, 5 hours takes about 4 days, 8 hours about 6, and 10 hours about 7. Shifting earlier instead would take 14 to 19 days.
Crossing the date line: you lose a day
Going to Australia, you skip most of a calendar day. Coming home, you land before you left. For example, a 10:30 PM Tuesday departure from Los Angeles with a 15-hour flight lands in Sydney at 8:30 AM on Thursday in the Australian summer. On the way back, an 11:30 AM Thursday departure with a 13.5-hour flight lands in Los Angeles at 6:00 AM that same Thursday.
Book everything by the local date.
When to sleep on the flight to Sydney
Sleep during Sydney's night, roughly 9:30 PM or 11:00 PM to 6:45 AM Sydney time, and stay awake before that. Here's that same 10:30 PM flight in all three time zones.
| Sydney time | LA body time | New York body time | What to do |
|---|---|---|---|
| 5:30 PM | 10:30 PM | 1:30 AM | Takeoff. Eat, stay up |
| 9:30 PM | 2:30 AM | 5:30 AM | Lights out if you can't last (6 cycles) |
| 11:00 PM | 4:00 AM | 7:00 AM | Lights out, better for shifting later (5 cycles) |
| 6:45 AM | 11:45 AM | 2:45 PM | Wake up, breakfast |
| 8:30 AM | 1:30 PM | 4:30 PM | Land |
Both use the site's sleep math: 15 minutes to fall asleep plus full 90-minute cycles. Staying up past your home bedtime goes with the grain on this trip. If you're connecting from the East Coast, you'll already have been traveling for hours, so the 9:30 PM option is the realistic one.
Night-by-night plan after you land
The trick is getting daylight before your body clock's low point and avoiding bright light in the few hours after it. That low point, the sleepiest time of your body's night, usually falls about 3 hours before your usual wake-up time. Light before it pushes your clock later, which is what you want. Light soon after it pulls your clock earlier, the wrong way for this trip.
Los Angeles to Sydney, November to early March (5 hours)
| Night | 11 PM feels like | Body clock low point | Light plan |
|---|---|---|---|
| Night 1 | 4:00 AM | 11:00 PM | Daylight all afternoon and evening |
| Night 2 | 2:30 AM | 12:30 AM | Same. Mornings are fine |
| Night 3 | 1:00 AM | 2:00 AM | Keep it dim until about 6:00 AM |
| Night 4 | 11:30 PM | 3:30 AM | Keep it dim until about 7:30 AM |
| Night 5 | adjusted | 4:00 AM | Morning light now helps lock it in |
New York to Sydney, November to early March (8 hours)
| Night | 11 PM feels like | Body clock low point | Light plan |
|---|---|---|---|
| Night 1 | 7:00 AM | 8:00 PM | Daylight in the afternoon, dim after 8:00 PM |
| Night 2 | 5:30 AM | 9:30 PM | Daylight into the evening, dim after 9:30 PM |
| Night 3 | 4:00 AM | 11:00 PM | Daylight all afternoon and evening |
| Night 4 | 2:30 AM | 12:30 AM | Same. Mornings are fine |
| Night 5 | 1:00 AM | 2:00 AM | Keep it dim until about 6:00 AM |
| Night 6 | 11:30 PM | 3:30 AM | Keep it dim until about 7:30 AM |
| Night 7 | adjusted | 4:00 AM | Morning light now helps |
These assume an average shift of 1.5 hours a day. Long Australian summer evenings make the light part easy: get outside after about 3 PM.
Expect to fade in the early evening and wake at 3 or 4 AM for the first few nights. If you shift your sleep 1 hour later a day for 3 days before you fly, you start with less to make up: about 2 days of adjustment from LA, and about 4 from New York.
Coming home from Australia
The trip home is usually harder, because your body now has to shift earlier. In the Australian summer, Sydney to Los Angeles is a 5-hour advance and Sydney to New York an 8-hour advance, roughly 5 and 8 days at an hour a day. Get morning light, keep evenings dim, and hold your normal wake-up time. Our US to Europe plan uses the same eastward approach, and east vs. west explains why it's slower.