Morning light therapy beats evening for late winter sleep

Morning light therapy works better than evening for improving sleep quality when your circadian rhythm is disrupted in late winter.

Here’s why: Late winter means short days and low morning light. Your internal clock relies on bright light in the early part of the day to stay synchronized. Without it, your circadian rhythm tends to drift later — you feel alert at night and groggy in the morning. That’s a delayed sleep phase, and it’s really common in February and March.

Morning light exposure (especially within 30 minutes of waking) signals your brain to stop producing melatonin and start the day. It also shifts your clock earlier, making it easier to fall asleep at a reasonable hour. Evening light does the opposite — it delays your clock further, which can make the problem worse. If you’re already struggling with late winter sleep, adding evening light is like pouring gas on the fire.

The practical move: a 10,000 lux light box for 20–30 minutes as soon as you wake up. Dim the lights after sunset. That’s the pair that actually works.

Your body wants morning sun even when the sun isn’t cooperating.