I discovered an error in the imperial_temp_graph section of make-graphs.sh, at least the version I am using, 0.0.1. There are many permutations of this script so my finding may already have been corrected. I did search this forum for a mention of this error and found none.
The calculation to convert Celsius to Fahrenheit is incorrect. the original script adds 32 to the Celsius temperature before multiplying by 1.8. This multiplication should come first in the formula.
If your version of the script has it wrong (and if you actually want to use the imperial temperature section) then replace the lines after “CDEF:tta=traw,1000,/” \ with the following:
"CDEF:ttb=tta,1.8,*" \ "CDEF:ttc=ttb,32,+" \
(My apologies for not adding this to the System Monitoring thread. That had been my intent.)