Outside temperature at any given altitude, preferably expressed in degrees centigrade.
ambient temperature
am·bi·ent tem·per·a·ture
(ambē-ĕnt tempĕr-ă-chŭr) The overall level of heat or cold in an environment.
ambient temperature
The surrounding temperature or that present in the place, site, or location indicated.See also: temperatureAcronymsSeetantalumThesaurusSeeroom temperature