I was diagnosed with Seasonal Affective Disorder a decade or so ago in an effort to explain my recurring depression which more often than not (but not perfectly) coincided with Autumn & Winter. It seemed to fit.
This year is the first time that I'm approaching winter with an autism diagnosis, and I've had a year or so to become comfortable with the fact that I have autism.
Things seem a little different. Now that I'm coming to know my autism and discern its shape in the murk, I'm more likely to describe the impact of winter along the lines of being less able to mask, and maybe having fewer "people spoons".
I'm wondering if I don't have SAD at all, but simply find that winter makes masking harder. Why, I don't know. But it feels possible somehow.