DHT11 Fluctuating terribly, anyone have any ideas?

My code as follows:

/*
  LiquidCrystal Library - Hello World
 
 Demonstrates the use a 16x2 LCD display.  The LiquidCrystal
 library works with all LCD displays that are compatible with the
 Hitachi HD44780 driver. There are many of them out there, and you
 can usually tell them by the 16-pin interface.
 
 This sketch prints "Hello World!" to the LCD
 and shows the time.
 
  The circuit:
 * LCD RS pin to digital pin 7
 * LCD Enable pin to digital pin 6
 * LCD D4 pin to digital pin 5
 * LCD D5 pin to digital pin 4
 * LCD D6 pin to digital pin 3
 * LCD D7 pin to digital pin 2
 * LCD R/W pin to ground
 * 10K resistor:(A pin and +5v)
 * ends to +5V and ground
 * wiper to LCD VO pin (pin 3)
 
 Library originally added 18 Apr 2008
 by David A. Mellis
 library modified 5 Jul 2009
 by Limor Fried (http://www.ladyada.net)
 example added 9 Jul 2009
 by Tom Igoe
 modified 22 Nov 2010
 by Tom Igoe
 
 This example code is in the public domain.

 http://www.arduino.cc/en/Tutorial/LiquidCrystal
 */

// include the library code:
#include <LiquidCrystal.h>
#include <dht.h>
#include <EEPROM.h>
#define dht_dpin A5
#define RELAY1  12
dht DHT;
int high_addr = 0;    //Where to store the settings
int low_addr = 1;     //Where to store the settings
int high_addr_h = 2;  //Where to store the settings
int low_addr_h = 3;   //Where to store the settings
int read_high_temp;   //Get and keep the high temp setting
int read_low_temp;    //Get and keep the low temp setting
int read_high_h;      //Get and keep the high humidity setting
int read_low_h;       //Get and keep the low humididty setting

// initialize the library with the numbers of the interface pins
LiquidCrystal lcd(7, 6, 5, 4, 3, 2);
int val;
int vala;
int valb;
int valc;
int vald;
int vale;
int valf;
int valt;
byte smiley[8] = {
  B00000,
  B01010,
  B01010,
  B00000,
  B00000,
  B10001,
  B10001,
  B01110,
  
};

byte frowney[8] = {
  B00000,
  B01010,
  B01010,
  B00000,
  B00000,
  B01110,
  B10001,
  B10001,
  
};




void setup() {
  pinMode(RELAY1, OUTPUT);   
  Serial.begin(9600);
  delay(300);
  Serial.println("Humidity and temperature\n\n");
  delay(1000);
  lcd.createChar(0, smiley);
  lcd.createChar(1, frowney);
  // set up the LCD's number of columns and rows:
  lcd.begin(16, 2);
  // Print a message to the LCD.
  lcd.setCursor(0, 0);
  lcd.print("Humidity|");
  lcd.setCursor(0, 1);
  lcd.print("Celsius |");
}

void loop() {
/*
  int read_high_temp = 29;   //Highest Temp Setting
  int read_low_temp = 28;    //Lowest Temp Setting
  int read_high_h = 100;     //Highest Humidity Setting
  int read_low_h = 75;       //Lowest Humidity Setting
  EEPROM.write(high_addr, read_high_temp);
  EEPROM.write(low_addr, read_low_temp);
  EEPROM.write(high_addr_h, read_high_h);
  EEPROM.write(low_addr_h, read_low_h);
*/
  
  DHT.read11(dht_dpin);
  //SET AND STORE DEFAULTS
  read_high_temp = EEPROM.read(0);
  read_low_temp = EEPROM.read(1);
  read_high_h = EEPROM.read(2);
  read_low_h = EEPROM.read(3);
  
  val = DHT.humidity - 0;
  vala = DHT.temperature;
  delay(500);
  valb = DHT.temperature;
  delay(500);
  valc = DHT.temperature;
  delay(500);
  vald = DHT.temperature;
  delay(500);
  vale = DHT.temperature;
  delay(500);
  valf = DHT.temperature;
  delay(500);
  valt = (vala + valb + valc + vald + vale + valf) / 6;
   
  if (val > read_high_h || val < read_low_h)
  {
    lcd.setCursor(10, 0);
    lcd.print(val);
    lcd.print("% |");
    lcd.setCursor(15, 0);
    lcd.write(byte(1));
  }
  else
  {
    lcd.setCursor(10, 0);
    lcd.print(val);
    lcd.print("% |");
    lcd.setCursor(15, 0);
    lcd.write(byte(0));
    
  }
  
  //READ is higher than SET HIGEST
  if (valt >= read_low_temp || val <= read_high_temp)
  {
    lcd.setCursor(10, 1);
    lcd.print(valt);
    lcd.print(char(223));
    lcd.print("C|");
    lcd.setCursor(15, 1);
    lcd.write(byte(0));
    digitalWrite(RELAY1,HIGH); 
    
  }
  else
  {
    lcd.setCursor(10, 1);
    lcd.print(valt);
    lcd.print(char(223));
    lcd.print("C|");
    lcd.setCursor(15, 1);
    lcd.write(byte(1));
    digitalWrite(RELAY1,LOW);
  }
  delay(500);
}

Video of whats happening:
Video of issue

damnit, just saw you might say that its just alternating between the next or previous readings. But it actually is alternating between 26 and 28 now, not 27 and 28. Why would that be?

Hi, Don't use the DHT11 it's not reliable, or so I've heard? The DHT22 is better and there are better ones but more expensive.... I should do something for the Greenhouse but only got around to Temp and light! But I could be wrong!

Regards

Mel.