Ok, a bit of a glitch I'm getting.
(running the last beta in Vista x 64, BTW)

When minimized to the system tray, the temps displayed bounce around as expected and hovering the mouse gives me the thumbnail but when running in the notification area the temps don't change at all, remaining static till the app is closed.
Reopening the program will give me a fresh set of numbers but then they stay the same.
In other words, the notification area doesn't seem to refresh.

Is this just me?