Arduino Uno Sensor DHT11 Failed to read from DHT sensor
There are several versions of the DHT11 library for Arduino out there. This is the one that worked for me: https://github.com/adidax/dht11. Here is a simple sketch to test the sensor with the output going to the serial monitor.

// 5k ohm pull up resistor is used on the data line.
// Sensor operates at 5VDC.
// Data line connects to Arduino Uno pin 3.

#include &lt;dht11.h&gt;
dht11 DHT11;
#define DHT11PIN 3

// Sensor calibration. Start with 0 for each.
const int HumidityCorrection = -10;          // -10 worked with my sensor.
const int CelsiusTemperatureCorrection = 2;  // 2 worked with my sensor.

const float FahrenheitTemperatureCorrection = CelsiusTemperatureCorrection * 1.8;

// Update the serial display every 60 seconds.
const float UpdateSerialDisplay = 60000;

// Celsius to Fahrenheit conversion.
double Fahrenheit(double celsius){
  return 1.8 * celsius + 32;
}

void setup(){
  Serial.begin(9600);
  // Minimum wait for good data recommended is 1 second.
  delay(2000);
  Serial.println("DHT11 TEST PROGRAM ");
  Serial.print("LIBRARY VERSION: ");
  Serial.println(DHT11LIB_VERSION);
}

void loop(){
  Serial.println("");
  int chk = DHT11.read(DHT11PIN);
  switch(chk){
    case DHTLIB_OK: 
      //Serial.println("OK"); 
      break;
    case DHTLIB_ERROR_CHECKSUM: 
      Serial.println("Read sensor: Checksum error"); 
      break;
    case DHTLIB_ERROR_TIMEOUT: 
      Serial.println("Read sensor: Time out error"); 
      break;
    default: 
      Serial.println("Read sensor: Unknown error"); 
      break;
  }

  Serial.print("Humidity: ");
  Serial.print("\t");
  Serial.print(DHT11.humidity + HumidityCorrection);
  Serial.println(" %");

  Serial.print("Temperature: ");
  Serial.print("\t");
  Serial.print(DHT11.temperature + CelsiusTemperatureCorrection);
  Serial.println(" C");

  Serial.print("Temperature: ");
  Serial.print("\t");
  Serial.print(round(Fahrenheit(DHT11.temperature) + FahrenheitTemperatureCorrection));
  Serial.println(" F");

  delay(UpdateSerialDisplay);
}


Once you get this working you can add the LCD code to it. Here is a link to the DHT 11 Humidity &amp; Temperature Sensor manual / data sheet: http://www.micropik.com/PDF/dht11.pdf