QUESTION:
With the soil temperature ranging around 60 degrees F, is there essentially
a seperate enviornment which exists between ground level and approximately 5
feet from the surface where temperature conditions change drastically? Do
the ground temperatures remain stable through the different seasons on Mars?

ANSWER from Mike Mellon on August 13, 1997:
Ground temperatures and air temperatures generally differ, perhaps more so
on Mars because the air is much thinner than Earth's (about 140 times
thinner). The surface of a planet absorbs much of the solar energy, where
the atmosphere lets the sunlight pass through it. So daytime high
temperatures are usually higher for the ground than the air.  An extreme
example might be walking on the sidewalk or a beach, barefoot on a hot
summer day. The air is hot, but the ground is much hotter and you could even
burn your feet. Similarly the ground can cool at night, more efficiently
than can the air, by infrared radiation.  On Earth this can result in a dew
or frost forming on the ground where warmer wet air contacts the colder
ground (much like water droplets forming on the outside of a glass of ice
water).

As for seasons, Mars experiences seasons like the Earth because of a similar
tilt in its spin axis. The Martian year, however, is about 687 Earth days
long. The average temperature on Mars is about -70 centigrade (-94
Fahrenheit). At the poles night time temperatures can fall as low as -125
centigrade (-193 Fahrenheit) at which point the carbon dioxide atmosphere
starts to condense on the ground as frost.  At the equator in the summer
ground temperatures can rise above freezing and even be quite comfortable
(to sit on - the air is still quite cold). But the dry atmosphere prevents
liquid water from collecting. The Pathfinder spacecraft landed near the
equator (19 degrees North latitude) and at a warm time of year at that
location (equivalent to late spring).

Mike Mellon