That's hot and cold at the same time: Three companies OKI, NYK Logistics Japan, and HILLS together developed passive RFID tags with integrated temperature sensors.

Sensor RFID tags usually require batteries, therefore they are active RFID tags. The new sensor tags are passive, meaning they operate without batteries (using only the power supplied by reader devices). Application areas of these tags include transportation and management of precision instrument, drugs and food.

via RFID in Japan