The earliest you could call them would be 11:00 am, central time zone
I do not know but i think that sierra nevada is further from the equator
The Rocky Mountains are described as younger because the Rocky's are really two mountain chains. The older mountain chain started billions of years ago, and the younger mountain chain pushed the older mountain chain up more, only 60 millions years ago.
Pacific Ocean
Sharing a common border throughout its northern extent with the United States, Mexico is bounded to the west and south by the Pacific Ocean, to the east by the Gulf of Mexico and the Caribbean Sea, and to the southeast by Guatemala and Belize.
Hope it helps you