Serial plotter isn't displaying my supplied data
You can't send arbitrary information (percent signs, text etc) to the plotter. The plotter only understands numeric values. You have to separate these number values from each other with commas, then do a println in your last value:

Serial.print(percent);
Serial.print(F(","));
Serial.print(tankPercent(depth));
Serial.print(F(","));
Serial.print(litres);
Serial.print(F(","));
Serial.println(tankLitres(depth));


In your case, it'd be simply:

Serial.println(DHT0.humidity);


You can go a bit further if you want to switch between either serial output, or serial plotter. In one case, I just set a constant variable for graph or plain data, then have a function for each (my above Serial statements are actually within a function called displayGraph()). The data function would be something like you had originally, example:


void displayData(float depth, float percent, float litres){

  // water level depth (inches)

  Serial.print(F("current missing inches: "));
  Serial.println(mixtureDistance());

  // cubic inches

  Serial.print(F("total cubic inches: "));
  Serial.println(TANK_TOTAL_CUBIC_INCHES);

  Serial.print(F("current cubic inches: "));
  Serial.println(tankCurrentCubicInches(depth));

  // litres

  Serial.print(F("total litres: "));
  Serial.println(TANK_TOTAL_LITRES);

  // ... etc
}


I also have projects where I use a switch that if on, sets a flag to output in serial graph format, and if off, uses the serial data routine.

Then, in your sketch loop(), you'd do something like:

graph
  ? displayGraph(depth, percent, litres)
  : displayData(depth, percent, litres);


...or a bit more verbose rather than using the tertiary operator:

if (graph){
  displayGraph(...);
}
else {
  displayData(...);
}


Here's a Q&amp;D serial plotter example of my displayGraph() function above. In the top-right corner of the image, the four colours represent the four pieces of data I'm sending in, in order:



In my case, those represent the exponential moving average of the percentage of how full a liquid tank is, the second is the raw data I'm building that average on, third is the exponential moving average of how many litres are remaining in the tank, and lastly, again, the raw data for that average.

The sharp movements are simply me slapping the tank to get some variable and unstable readings for example purposes.