Make it easier with color changing
Declare a local variable to hold the color:

var
  Color: TColor;


Then decide what the color should be:

if Temperatura&lt;=15 then
  Color:=clBlue;
else if Temperatura&lt;=18 then
  Color:=clAqua;
else ...


Then assign the color to the controls:

Form1.Label1.Font.Color:=Color;
Form1.Label2.Font.Color:=Color;
....


The labels could be stored in an array or a list. So that you can iterate over them to assign the color. You could declare the array like this, in the form class:

FLabels: TArray&lt;TLabel&gt;;


In the constructor assign it like this:

FLabels := TArray&lt;TLabel&gt;.Create(Label1, Label2, Label3, Label4, Label5);


To iterate over it setting the color do this:

var
  lbl: Tlabel;
....
for lbl in FLabels do
  lbl.Font.Color:=Color;


You appear to be using a global variable Form1. Your code will be better without that global variable, and having this procedure (and others like it) converted into a method of the form.