Essential for meterology, medicine, industry and scientific research, thermometers are not the result of a single invention but an evolution spanning about 2000 years. 

Featuring an antiqued finish, the coin is inset with an operational dial thermometer. Including both Celsius and Fahrenheit scales. The thermometer's face portrays an Aztec-style sun in the middle, surrounded by Aztec-style patterns and iconography based on the circular Aztec agricultural, or solar, calendar. 

The coin's obverse reveals the thermometer's sensor which is encircled by Aztec-style patterning, the Ian Rank-Broadley effigy of Her Majesty Queen Elizabeth II, monetary denomination and 2018 year-date.