The Viking Orbiter Infrared Thermal Mapper showed a peak temperature of 81F. Together with a mean surface pressure of about 600 pascals, much lower than the Earth’s 101,000 Pa.
http://en.wikipedia.org/wiki/Climate_of_Mars#Temperature
According to NASA, the solar wind stripped away much of the Martian atmosphere, and I imagine much of its water as well.
http://science.nasa.gov/science-news/science-at-nasa/2001/ast31jan_1/
The point is, Mars didn’t have much if any in the first place.