Temperature Sensor Test
Open the Arduino IDE and open Adafruit's temperature sensor test sketch by navigating to File -> Examples -> Adafruit MCP9808 Library -> MCP9808test
Since the default address on the MCP9808 is 0x18 by default (on the LTE shield you can't change it, sorry!) the example sketch should work right off the bat! Just make sure you select the correct baud rate in the serial monitor (9600). You might also need to un-comment the "tempsensor.wake();" line in loop() in order to get readings if you previously had it go to sleep! Here's a sample of the temperature values in the serial monitor:
