There must be some wind currents that simply bring the clouds up and down like a roller coaster, 'cause my horizon is straight, but the clouds are on a swing. You can see the same in the picture bellow (same place, a little later)
Most people will see the sun rise and set always toward the east, and west. Here the sun is setting (in Iceland), May 5, 10:45 PM on the clock, and that point is north west.
Exif 2 frames: ISO 100 ; f/22 ; 1 sec ; @14mm
Reverse ND Grad 0.9