nicole: Clouds over Mars, photographed by Mars Global Surveyor, 2001.
13 pairs of images, taken through blue (left) and red (right) filters, 14th February-5th June 2001; Ls 117.0° to Ls 173.5°, the latter two thirds of the northern summer.
At the top of each gif is the north polar cap. The light area at the bottom is the northwest edge of the massive Hellas Planitia basin (the bright crater on its rim is Terby, 170km across). Left of centre are the Syrtis Major highlands; right of centre is the Isidis Planitia; you can definitely see clouds affected by the terrain’s change in altitude.
Image credit: NASA/JPL/MGS/MSSS. Animation: AgeOfDestruction.