The clouds are a dramatic visualization of the Martian water cycle. The water vapor comes off the north pole during the peak of summer. The northern-Mars summer has just passed its peak water-vapor abundance at the Phoenix site. The atmospheric water is available to form into clouds, fog and frost, such as the lander has been observing recently.
I wait for the day when we’ll get a glimpse of Titan’s weather from the surface eye of a probe. Another twenty, thirty years, most likely.