Yah, that sounds pretty reasonable. Realistic idle temps will
generally be 2C to 5C over the temperature of the air going into the heatsink fan, and unless you've got air flowing directly into that fan from outside the case, that will usually be around 1C to 2C over the ambient temp. So it sounds like you're right in that range.
I wish Intel designed the chips so that Tjunction could be read from a processor register
The temps are meaningless without knowing Tjunction. It's like having a really nice thermometer w/ only one mark on it, and telling everyone, "my temperature is 50C below the mark", with no idea what temperature the mark is. Meanwhile somebody else comes along and starts telling everyone the mark is either 85C or 100C, when the real mark may be somewhere in between, above, or below those two numbers.