Link: http://www.guardian.co.uk/science/2009/jan/27/mars-snow-space-technology-nasa

... or at least in the sky above it. This is just one extraordinary piece of information being sent back to us by the landers, probes and rovers scanning the planet. Home to the largest mountain in the solar system and a canyon as long as the US is wide, it is a world as fantastic as any imagined by JG Ballard.

High in the sky above Mars, it is snowing right now. Very gently snowing. The snow does not settle on the rubble-strewn land below - not these days, anyway - but instead vaporises into the thin atmosphere long before it reaches the ground. The first flakes of snow, on a planet that until fairly recently was believed to be waterless, were spotted just a few months ago. A Nasa lander near the planet's north pole was scanning the sky with a laser when it noticed the telltale signs of snowfall. The probe, called Phoenix, announced the news in a radio signal that was picked up by an overhead orbiter and beamed back to Earth. Nothing like it had ever been seen before.