As we step into autumn and the light begins to shift, consider this a gentle lead-in to winter not far away. Winter doesn’t just change the weather; it changes your biology, as shorter days, dim indoor light, and bright screens at night quietly rewrite when you feel sleepy, when you wake, and how your sleep unfolds. If your nights start to feel different as winter approaches, there’s a circadian reason. Table of Contents: How Winter Light Rewrites the Night What winter really