Our FB100 (Non-WiFi) and FB200, FB300 & FB500 (WiFi-Enabled) controllers have a setting in the menu selections to switch temperature readings between Fahrenheit and Celsius. On the Flame Boss® 200/300/500, press the "Menu/Next" button until you get to the screen that says "Other [Skip]", press the "Up" arrow button to change [Skip] to [Enter], and then press "Menu/Next" button until you see the "Temperature Scale Fahrenheit". Press the "Up" or Down" arrow until it says "Celsius" and press "Menu"
There is also a setting to view the temperature readings in Fahrenheit or Celsius on your device display in the "Profile" section of the MyFlameBoss.com web app. Click on the Settings link for the device you would like to edit.
The Temperature Scale setting is also found on the "Devices" tab in the Flame Boss® mobile apps and all of our WiFi-enabled controllers mentioned above for our FB WiFi Thermometer. Click on the gray cog wheel 
and then the MORE button.
The Temperature Scale setting for your cook show page can be found on the Account tab on your mobile app.
If you need further assistance, please click here to Contact Us or call us at 800-978-9078.