Cold air is more dense than warm air, the slight change has caused the light to come on. When it warms up outside the light will turn back off or you could put a little air in each tire to get the light to turn off.
Nope, according to the manual and side sticker in the driver side door jam, all tires should have 35 psi.+10000 to what RKB said
If you're filling your tires up with air, just make sure not to overdo it. I think the PSI in there should be around 32lbs
Someone correct me if I'm wrong