The Weather Eye was a trade name for a Nash Motors-designed fresh-air automotive heating system first used in 1938. This "Conditioned Air System" is characterized by a cowl-mounted outside air receiver that then passes fresh air through a heater core utilizing hot engine coolant for a heat source. In 1939, Nash added a thermostat to its Conditioned Air System, and thus the famous Nash heater was first marketed. The use of the Weather Eye name for automobile heating and air conditioning systems continued in American Motors (AMC) vehicles.
The famed "Weather Eye" was developed concurrently with the much lesser-known but contemporary Hupmobile Evanair-Conditioner that took its fresh air through special hood scoops. The principles of both the Hupmobile Evanair-Conditioner and the Nash Weather Eye are still in use today in nearly every motor vehicle.
The phrase "to keep a weather eye" on something, means to maintain a background awareness of something; to remain alert to changes without it occupying your full attention. The term is nautical, originating from seamanship.
- Wolfe, Steven J. (2000) HVAC Time Line, Refrigeration Service Engineers Society Twin Cities Chapter, retrieved on January 11, 2009.
- Heppenheimer, T.A. (2005) "Cold Comfort", Invention &Technology Magazine 20(4), retrieved on January 11, 2009.