I would also like to see some ground temperature readings released now as well. One of the Phoenix instruments determines actual ground temperatures (rather than air temperatures) and the thermal inertia of the soil. It's called the Thermal and Electrical Conductivity Probe (TECP). It's located on the Phoenix robot arm. It may be able to tell if there is liquid water on Mars. This page describes it:

Sunning Frozen Soil.
Summary (Jul 21, 2006): The answer to the question about life on Mars may very well come from analyzing an unsuspecting source - the soil, specifically the icy layer of soil underneath the red planet's surface. By analyzing the properties of Mars frozen layer of soil during NASA s next lander mission, scientists will be able to better understand and theorize about life on Mars.
http://www.astrobio.net/news/modules.php?op=modload&name=News&file=article&sid=2028

Bob Clark