How come the sun sets in Santa Monica, CA before Alberta Calgary, but after Phoenix?

Question

How come the sun sets in Santa Monica, CA before Alberta Calgary, but after Phoenix two hours before ?

http://www.wunderground.com/US/CA/Santa_Monica.html

http://www.wunderground.com/global/stations/71877.html

http://www.wunderground.com/US/AZ/Phoenix.html

Answer 1

Santa Monica (34°N) is far South of Alberta (48+°N), and Phoenix (33°N) is South of Santa Monica.

L ≈ 2(arccos(- tan(φ)tan(- 23.45°cos[(360°/365)(N + 10)])))/15°

where

L = length of day in hours,

φ = latitude, and

N = days from Jan. 1

Note that after the Autumnal Equinox, the situation is reversed.