Can someone explain why when I load the save the temperature of wifi and other electronics decreases by 0.15?
Because the temp property is stored in saves as an integer on the Kelvin scale (unless it's less than 128K off from room temperature, in which case it's stored as a signed 8-bit offset from that).
Sorry, but I know little about computers. How can I fix this? I tried to add 0.15 to the temperature but that did not help.