TTh's (and also BT's) large Temperature Graph now contains, in addition to "hours ago" (or "minutes ago") markers at thick green vertical lines, also a true wall-clock timeline, which is exactly explanatory regarding the past time. But if the computer gets asleep for some time, after it awakes, it is not true anymore.
I've been thinking about whether (at all) to try to take the interruptions into account (this is actually up to the author, as usual), and how to display them graphically. The simple numbers "hours/minutes ago" could be kept interpreted as "run-rime ago", and a double thick green vertical line would simply mark the place of interruption. But this idea does not play with true wall-clock time. Is it some brainstorming worth?