The science
The same light can move your clock either way
Light can move your body clock earlier or later. When you get it matters as well as how bright it is.
Timing follows your body clock
Broadly, light in the hours before your body's lowest temperature point tends to move your clock later, and light in the hours after it tends to move it earlier. The changeover is not an exact dividing line that works the same for everyone.
Seeking light
Your plan may ask you to seek daylight at particular times. The aim is to help move your clock toward the timing of your trip, rather than to get as much light as possible all day.
Avoiding light
Light at another time may push your clock in the opposite direction. During a light-avoidance period, your plan may suggest dim lighting, screens off or an eye mask, depending on where you are.
What the studies can tell us
Laboratory studies show that timed light can shift body-clock timing. They do not tell us exactly how much your clock will shift with the daylight and lighting you meet on a journey.
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