My joints don't actually ever visibly swell but I do get painful joints from sun but also from overdoing things in general. Not overusing the joint, just overusing myself - haha - getting too tired.
A good example was this weekend when I walked a tiny bit more than the 20 minutes I can just manage. Obviously I really hurt my feet but also, Sunday pm (after walking a bit Sat afternoon) I suddenly felt really awful, crushing tiredness and joint, tendon, muscle, nerve pain. The whole lot. It was also relatively dry (though not sunny) so, although I was completely covered up, sunscreen etc. who knows which was worse - the walking or the "sun".
sorry, I'm not much help on a clear answer am I?