Of course, the Ecobee's value for outside temperature isn't being measured outside of your house. It is from weather data for your local area. Therefore, there's nothing really to be gained from getting your outside temperature from the thermostat over using a weather API as suggested.
Looking for a Rule to properly use it against inside temp.
A basic rule I created last night based on temp on a trigger of the API > Ecobee house temp -2 kept triggering each time the API temp changed which is not what I want.
Ideally, I am looking to get a notification when the outside temp drops below inside temp
create local var as boolean: latch
trigger:
house temp changed
outside weather changed
action
if outside<house then
if latch then exit rule
send notification
latch = true
else
latch = false
end if