Error on my Processing GUI code for Arduino , I need some help

Processing Electronics (Arduino, etc.)
36

I’ve changed the code to :

import processing.serial.*;


Float winddir;
Float windspeedmph;
Float windgustmph;
Float windgustdir;
Float windspdmph_avg2m;
Float winddir_avg2m;
Float windgustmph_10m;
Float windgustdir_10m;
Float humidity;
Float tempf;
Float rainin;
Float dailyrainin;
Float pressure;
Float batt_lvl;
Float light_lvl;

 String a1 = winddir.toString();
 String a2 = windspeedmph.toString();
 String a3 = windgustmph.toString();
 String a4 = windgustdir.toString();
 String a5 = windspdmph_avg2m.toString();
 String a6 = winddir_avg2m.toString();
 String a7 = windgustmph_10m.toString();
 String a8 = windgustdir_10m.toString();
 String a9 = humidity.toString();
 String a10 = tempf.toString();
 String a11 = rainin.toString();
 String a12 = dailyrainin.toString();
 String a13 = pressure.toString();
 String a14 = batt_lvl.toString();

String myString = null;
Serial myPort;







void setup(){}
{
size(700,700);
String portName = Serial.list()[5]; 
myPort = new Serial(this, portName, 9600);
myPort.clear();
myString = myPort.readStringUntil('!');
myString = null;
}
void draw(){
  
 a1 = winddir.toString();
 a2 = windspeedmph.toString();
 a3 = windgustmph.toString();
 a4 = windgustdir.toString();
 a5 = windspdmph_avg2m.toString();
 a6 = winddir_avg2m.toString();
 a7 = windgustmph_10m.toString();
 a8 = windgustdir_10m.toString();
 a9 = humidity.toString();
 a10 = tempf.toString();
 a11 = rainin.toString();
 a12 = dailyrainin.toString();
 a13 = pressure.toString();
 a14 = batt_lvl.toString();
}
{
  while ( myPort.available() > 0) 
  {  
  myString = myPort.readStringUntil('!'); 
  if (myString != null) {
    println(myString);
    
    
    
      String[] q = splitTokens(myString);

      
    
    
    
    
       a1 = parseFloat(q[0]);
       a2 = parseFloat(q[1]);
       a3 = parseFloat(q[2]);
       a4 = parseFloat(q[3]);
       a5 = parseFloat(q[4]);
       a6 = parseFloat(q[5]);
       a7 = parseFloat(q[6]);
       a8 = parseFloat(q[7]);
       a9 = parseFloat(q[8]);
       a10 = parseFloat(q[9]);
       a11 = parseFloat(q[10]);
       a12 = parseFloat(q[11]);
       a13 = parseFloat(q[12]);
       a14 = parseFloat(q[13]);
       a15 = parseFloat(q[14]);

      
background(0);
textSize(20);
text("Wind direction:",50,50);
text(a1,250,50);
text("Wind speed:" ,50,100);
text(a2,250,100);
text("Wind gust:",50,150);
text(a3,250,150);
text("Wind gust direction:",50,200);
text(a4,250,200);
text("Humidity:",50,250);
text(a5,250,250);
text("Temperature",50,300);
text(a6,250,300);
text("Rainfall:",50,350);
text(a7,250,350);
text("Daily rain:",50,400);
text(a8,250,400);
text("Pressure",50,450);
text(a9,250,450);
text("Battery level:",50,500);
text(a10,250,500);
text("Light level:",50,550);
text(a11,250,550);

     
   }
  } 
}

And now the error is : cannot convert from float to String - line 86