Sorry Nick, I don't engage in flame wars.

I take it your statement:

"There is no liquid water in this shot. TES average temperatures are ~170K (-100 C), although there is quite a range in this scene wth the darker patches warmed by the sun to as much as ~200K (-70 C), depending on exact direction of local slope, and the ice at ~147K (-125 C)."

was meant to indicate the temperature at this location at this time.

Sorry I took it to mean the average over the entire year.

I thought the TES readings only gave an average temperature at a resolution of 3km. Are you estimating the maximum temperature at this site? I agree though an average temperature of -100C over a 3km wide area makes it unlikely 0C is reached at some spot in that region at this time.

The last image in the animation on the "South Polar Cap Recession" page is at 251 degrees solar longitude. It appears to show large portions of Mars at 70S latitude at around 0 degrees temperature:

South Polar Cap Recession
http://wwwflag.wr.usgs.gov/USGSFlag/Space/MGS_TES/spole99.html

I presume at 260 degrees solar longitude the temperature would be warmer.

You can't tell specific sites from this animation however. But it may be that at the site of image M1001115 at some time later on in summer 0 degrees C is reached.
It seems to me unlikely that the gullies even if they occur seasonally would disappear over only a year. So it may be that channels seen in this image actually formed in earlier seasons when 0 degrees was reached.

Bob Clark