Today's Image of Mars was taken by HiRISE in an attempt to image ice covered dunes, but it turned out that area was slightly overcast!
Just like here on Earth there are clouds on Mars! These are fairly thin clouds, so we can still make out the ice covered dunes below. The clouds are likely made up of tiny carbon dioxide ice particles, but occasionally they can be made up of tiny water particles! Unfortunately that doesn't mean that it rains on Mars, but scientists have determined that it does snow! The only problem is that they have never seen the snow touch the ground, so it can't be easily used as water by future explorers!
Clicking on this image will take you to the original high resolution image from HiRISE. Check it out!