An organic package substrate (120, 200, 300, 400, 500, 600, 700) comprising: a cavity (149, 249, 349, 449, 549, 649, 749) formed within the organic package substrate (120, 200, 300, 400, 500, 600, 700); and a package-integrated piezoelectric temperature sensing device, comprising: a base structure (136, 236, 336, 436, 536, 636) that is positioned in proximity to the cavity (149, 249, 349, 449, 549, 649, 749); an input transducer (131, 231, 331, 431, 531, 631, 731) coupled to the base structure (136, 236, 336, 436, 536, 636, 736), the input transducer (131, 231, 331, 431, 531, 631, 731) having a first piezoelectric material (134, 334, 434) to generate vibrations which are transmitted on the base structure (136, 236, 336, 436, 536, 636, 736) in response to input signals being applied to the input transducer (131, 231, 331, 431, 531, 631, 731); and an output transducer (141, 241, 341, 441, 541, 641, 741) coupled to the base structure (136, 236, 336, 436, 536, 636), wherein the output transducer (141, 241, 341, 441, 541, 641, 741) has a second piezoelectric material (144, 344, 444) to receive the vibrations and to generate output signals which are used to determine a change in ambient temperature. a cavity (149, 249, 349, 449, 549, 649, 749) formed within the organic package substrate (120, 200, 300, 400, 500, 600, 700); and a package-integrated piezoelectric temperature sensing device, comprising: a base structure (136, 236, 336, 436, 536, 636) that is positioned in proximity to the cavity (149, 249, 349, 449, 549, 649, 749); an input transducer (131, 231, 331, 431, 531, 631, 731) coupled to the base structure (136, 236, 336, 436, 536, 636, 736), the input transducer (131, 231, 331, 431, 531, 631, 731) having a first piezoelectric material (134, 334, 434) to generate vibrations which are transmitted on the base structure (136, 236, 336, 436, 536, 636, 736) in response to input signals being applied to the input transducer (131, 231, 331, 431, 531, 631, 731); and an output transducer (141, 241, 341, 441, 541, 641, 741) coupled to the base structure (136, 236, 336, 436, 536, 636), wherein the output transducer (141, 241, 341, 441, 541, 641, 741) has a second piezoelectric material (144, 344, 444) to receive the vibrations and to generate output signals which are used to determine a change in ambient temperature. a base structure (136, 236, 336, 436, 536, 636) that is positioned in proximity to the cavity (149, 249, 349, 449, 549, 649, 749); an input transducer (131, 231, 331, 431, 531, 631, 731) coupled to the base structure (136, 236, 336, 436, 536, 636, 736), the input transducer (131, 231, 331, 431, 531, 631, 731) having a first piezoelectric material (134, 334, 434) to generate vibrations which are transmitted on the base structure (136, 236, 336, 436, 536, 636, 736) in response to input signals being applied to the input transducer (131, 231, 331, 431, 531, 631, 731); and an output transducer (141, 241, 341, 441, 541, 641, 741) coupled to the base structure (136, 236, 336, 436, 536, 636), wherein the output transducer (141, 241, 341, 441, 541, 641, 741) has a second piezoelectric material (144, 344, 444) to receive the vibrations and to generate output signals which are used to determine a change in ambient temperature.