I had a look at this website today. Am on BA49 LHR-SEA on 27 December so take off at 1430 and land 1605. I had already chosen a starboard side window seat and was looking forward to seeing Greenland and perhaps the arctic. I take off and land during the daytime so presumed the who flight was in daytime - how wrong I was!

Looks like sunset about 1.5 hrs in to the flight and then a reverse sunset as we head back in to the daylight close to the end of the flight, followed by sunset again in Seattle of course. Colleague at work suggested that I may be lucky and get a northern lights show though so the shades are staying firmly open!