We choose to go to the moon... not because it is easy, but because it is hard.
Watch Earth and Mars dance around their current pressures and temperatures. Mars pressure's consistancy is one of the reasons there is so little cloudcover. Earth has varying pressures, which would lead to higher and lower temperatures, humidities, and clouds. Try to pick out when Earth is colder than Mars... that may be when you want to go!
Here is an animation of temperature on Mars, by month. It is helpful for determiing the best time to go to Mars. The data is displayed and animated in degrees Kelvin (K).