I don't think it's the high temp light... it's the low temp light. When I test drove the Mirage in Ottawa (Ontario, Canada), that's what the sales person told me.
Correct me if I'm wrong, but the light you're talking about isn't red ... I seem to remember it's blue or green. I saw it come on in the CVT car that had been sitting overnight, but not in the 5-speed car I tried that had been driven earlier that afternoon.
It's essentially a reminder to take it easy on the car until the temperature starts to come up to normal.
Hopefully one of the other owners will confirm.
EDIT: did you get an owner's manual with the car? I bet it's in there.
View my fuel log 2014 Mirage SE 1.2 manual: 58.7 mpg (US) ... 25.0 km/L ... 4.0 L/100 km ... 70.5 mpg (Imp)