I think it's just Arizona but I'm not positive...? They get plenty of sunshine throughout the year anyway so they don't necessarily need it...not like us NYers who suffer through 9 months of winter!!
The point of it is to get more sunshine during the hours most people are awake. I think....At least that's the point of it for me!! I get to take Duncan to the dog park finally because I'll be home from work before dark for a change! YEAH!