Yeah, I'm not used to looking at HWMonitor, but I believe that's correct.
The "Minimum" represents the lowest temperature the program has recorded while its been open. The "Maximum," naturally, is the highest. Looks like yours idles at around 35 *C and hit 51 *C while you were doing something that stressed the CPU a little.
If you leave HWMonitor running and then go play a game or run a stress test (or do whatever you do that pushes the hardware the most), HWMonitor will record the hottest temperature your processor got during that time under the Max column. I would say that if you kept it under 60 *C or so at the worst, then you're in great shape. You're "safe" up to 70 or so, but I wouldn't recommend letting it get much hotter than that.