NASA scientists said on Monday that the computer models they have been using to predict what the weather would be like on Mars are wrong, and more accurate models would give a better picture of its past.

Phoenix (Mars probe) mission scientists laid out the early harvest from five months of robotic operations on the northern polar region of Mars. The team collected daily weather reports, information considered critical to learning if the planet could have supported water long enough for life to evolve.

"It's a very active weather environment," lead investigator Peter Smith said. Phoenix saw dusty summer days slip into cloudy fall, replete with ground fog, snow and frost.