How to run an app shortcut or a tasker task when battery temperature is above a custom threshold?
Use the "Broadcast receive" block with "Battery changed" action, the broadcast "extras" will include a "temperature" entry:
http://developer.android.com/reference/android/os/BatteryManager.html#EXTRA_TEMPERATURE

Here's an example flow for getting the battery temperature:
http://llamalab.com/automate/community/flows/655