No, neither car has an external temp gauge, but we both have one fitted from birth. A single finger out the window, works a treat.
Has variable sensory readings, from freezing cold to b''' hot.
Mind you it varies greatly between static temps non moving vehicle to the variable speed affected wind chill factor on any given day.
We do something completely different on the bike thou, we wring out the sweaty shirts and weigh the water, not accurate but a good indicator of just hot or boiling hot.
Climate control systems need them, to keep the internal temps roughly 7 deg lower than external temps, and it is also curiosity breaker for occupants.
They are a gimmick really.