MarsSurface Temperature: Much colder than Earth with mean temperature of -63 degrees C and low -140 degrees C.
Atmosperic Pressure: Too low to survive without pressurized suits or environments.
Atmosphere: The Martian atmosphere consists mainly of carbon dioxide. However the partial pressure of CO2 at the surface of Mars is some 52 times higher than on Earth, possibly allowing Mars to support plant life.
Gravity: Roughly one third Earth norm.
Radiation: Limited protection from atmosphere.
Source of this page comes primarily from: Wikipedia, Colonization of Mars, http://en.wikipedia.org/wiki/Colonization_of_Mars.
More information coming soon.