@akya the number of times you can read a DHT11 in a given time period isn't limited. You can read as fast as you want. The limit widely mentioned (at various rates of around once every 2 seconds) has to do with the heating effect of turning on current to the temperature sensitive resistor to take a reading. Someone tested and noticed that reading at high speed caused a slightly elevated temperature reading. You can test for yourself and see at what read rate you notice an increase, or just limit to once every 2 seconds or less.