Read a temperature from A0, print to LCD at 0x3F.

temperature.pde

#include <Wire.h>
#include <LiquidCrystal_I2C.h>

#define I2C_ADDR 0x3F
#define TEMP_SENSOR A0

LiquidCrystal_I2C lcd(I2C_ADDR, 20, 4);

void setup() {
   lcd.init();
   lcd.begin(16, 2);
   lcd.backlight();

   uint8_t degree[8] = { 0b0110, 0b1001, 0b1001, 0b0110 };
   lcd.createChar(0, degree);
}

void loop() {
   int tempRead = analogRead(TEMP_SENSOR);

   float voltage = tempRead * 5.0 / 1024.0; 
   
   lcd.setCursor(0, 0);
   lcd.print(String(voltage));
   lcd.print(" volts");

   // now print out the temperature
   float temperatureC = (voltage - 0.5) * 100 ;  //converting from 10 mv per degree wit 500 mV offset to degrees ((voltage - 500mV) times 100)
   
   lcd.setCursor(0, 1);
   lcd.print(String(temperatureC));
   lcd.write(0);
   lcd.print("C");
   
   delay(1000);                                     //waiting a second
}