reduce number of Serial.print

Or best of all (I think) write a function! eg

you code

      //sensor1
      Serial.println("");
      Serial.print("Sensor1 ");       
      Serial.print("Humidity: ");
      Serial.print(humidity);
      Serial.print(" %\t ");
      Serial.print("Temperature: ");
      Serial.print(temp_c);
      Serial.println(" *C");
      
      //sensor2    
      Serial.print("Sensor2 ");    
      Serial.print("Humidity: ");
      Serial.print(humidity2);
      Serial.print(" %\t ");
      Serial.print("Temperature: ");
      Serial.print(temp_c2);
      Serial.print(" *C");
      Serial.println("");
      
      //sensor3   
      Serial.print("Sensor3 ");    
      Serial.print("Humidity: ");
      Serial.print(humidity3);
      Serial.print(" %\t ");
      Serial.print("Temperature: ");
      Serial.print(temp_c3);
      Serial.print(" *C");
      Serial.println("");
void printHumidity(int sensor,humidity,temp){
      Serial.print("Sensor");
      Serial.print(sensor);// my addition
then prints for the humidity temp etc

}

When ever you have code which is repeated use a function it is what they where invented for and it reduces the number of bugs you get.

Mark