Which side is the sunset on my flight?
The sunset side is the one question with a genuinely exact answer. The sun's position is calculated, not guessed, so all that matters is where your aircraft is pointing while the sun is low.
How the sunset side is worked out
We sample points along your route, estimate the heading at each one, and compute the sun's bearing and height at the times you will actually be there. If the sun sits clockwise of your heading you are looking at a right-window sunset; counter-clockwise means left.
Height matters as much as direction. A sun just above the horizon paints the whole window; a high sun mostly gives glare.
Rules of thumb
Flying north in the evening: sunset on the left. Flying south in the evening: sunset on the right. Flying west: the sunset is ahead of you and both sides get colour, so pick the side away from the glare.
Long evening flights heading east chase the dark, and the best colour ends up behind you — a rear window on the sunset side helps.
Cloud does not cancel a sunset
We fold in cloud cover and visibility along the relevant part of the route, so a spectacular sun angle under heavy cloud scores lower but never drops to zero. Broken high cloud often makes a sunset better, not worse.