Today it hit me too. I think it’s the cloud cover, cooler temps and mostly the sunlight. I love May/June/July for the daylight. My body responds more to that time frame mentally, no matter what my weather desires are. I also love May because you know you’ve got months of high-end daylight.
If it wasn’t for skiing, I’m not sure how I’d do winters these days. The darkness, dreary days, etc. It hits me differently in my mid-30s vs when I was in college, ha. At least skiing keeps me sane.