The Anova app is the best way to help you cook like a pro, but you can change the temperature scale directly on your Anova Precision Cooker Nano.
CHANGING TEMPERATURE SCALE
Press and hold the Current Temp button for 3 seconds located in the upper left of the display.
Temperature units will toggle between fahrenheit and celsius.
Repeat step 1 again to toggle between celsius and fahrenheit until desired temperature scale is displayed.