Sunshine gives you Vit D. Perhaps you are low in vit D and this is helping you. Vit D helps with pain. Maybe your vit D isn't a good one? Are you taking D3?

Plus, who is not emotionally happier with the sun shining compared to rain?

Also, were you perhaps moving around more than you normally do??? I have found the more I sit around and "baby" my feet, the more they actually hurt. The more I do and exercise the less they hurt.