Hi JC,
There are no tags for these, but it's a good idea so will add something during the 1.1 development - probably a new type to the STAT$ tag - something like STAT$TEMPERATURE:RANGE:THISYEAR$ for example.
[Edit: This could probably be done at the moment in something like php with tags to find the maximum across the range and subtracting the minimum.]
Thanks for the suggestion,
Stu.