Stack bright light before midnight, block blue after.

For night shift workers with late-winter SAD, the key is timed bright white light during the early part of your shift and strict blue-blocking for the last few hours and after.

SAD is caused by insufficient morning light, but you don’t get a real morning – you sleep during the day. So you fake it. The goal is to push your circadian rhythm so your “day” starts when you clock in and ends when you walk out. Light is the lever.

Here’s what I’d do: First half of your shift, get a bright white light (10,000 lux, a therapy lamp or overhead fluorescents) in your field of view for 30-60 minutes. This is your “sunrise.” Then about 3-4 hours before the end of your shift, switch to dim, warm lighting if you can. Put on blue-blocking glasses (amber or red lenses) for the last hour of work and keep them on during your commute home – especially if you’re driving under streetlights or using your phone. When you get home, immediate bedtime routine in nearly total darkness. No screens without heavy blue filters.

The winter part just means you skip any temptation to “get morning sun” after your shift. Don’t. That would pull your rhythm into daytime, which fights the night shift. You want your body to think your shift is daytime.

This is not a perfect fix, but it beats the default of “stumble through a dark winter night, sleep