How do you power your setup?
Via a USB cable connected directly to the computer. Then from 5v on the Arduino to the red +ve rail on the breadboard also the Gnd from the arduino to the -ve on the breadboard.
You noticed that in your posted sketch you don't print the average value but the last reading?
I thought I did. In the getVolts routing I do a
Serial.print("Input Value: ") ; Serial.print(inputValue);
Serial.print(" | Voltage: ") ; Serial.print(volts);
each time the routing is called. While debugging I did print each read and then printed the lines in the above code.
When the getTemp() routing is called I also print the value after my calculation.
Serial.print(" | Temperature: "); Serial.print(temp); Serial.println(" 'C");
In the loop() routine I simply print value from (sensor connected to A1 + sensor connected to A2) divided by 2.
What is puzzling is the metered reading from the 2 sensors is the same (620mV) but the reading from the ADC is so different.