I've been monitoring the soil temperature and moisture in my area since early September of '08 and graphing the results. I've been studying the behavior of the grass in regards to the changing temperature to better understand a few things, and I just thought I'd share the graphs with everyone here. The soil temperature warmed up quite a bit last week because of the heat wave, but it's since dropped due to winter shifting back in.

Soil Moisture

Notice the moisture during Dec-Feb in the following graph.
The ground is frozen 4 inches down, so there is little to no moisture available to the roots at the depth.

Soil Temperature

Starting to warm back up...

But, cooling back down for a little while... (3/6/09 - 3/12/09)