Late-winter SAD usually means a delayed clock—afternoon melatonin helps, evening light hurts.

Melatonin secretion in late-winter SAD is typically phase-delayed (shifts later), and the evidence suggests low-dose melatonin taken in the late afternoon or early evening can help phase-advance, while evening bright light will make things worse.

Here’s the quick version: Seasonal affective disorder in late winter tends to push your circadian rhythm later, not earlier. Your melatonin onset creeps toward bedtime or even after. That makes waking up miserable and leaving you groggy all morning. The standard fix is morning bright light, which pulls your clock forward.

But if you’re asking about low-dose melatonin or evening light as alternatives—only one of those works. Low-dose melatonin (0.5 mg or less) taken about 4-6 hours before your natural melatonin onset (usually late afternoon/early evening for most people) can nudge your clock earlier. It’s a gentle