Answer 1

<?php
$grad =30;

if ($grad<=30 && $grad>=20)
{
echo "Sommer time!";
}
elseif ($grad <=15 && $grad >=0)
{
echo "It is cold";
}
else{
echo "Please write a grad between 15 and 30";
}
?>

Answer 2

What help do you need?

Answer 3

Its working fine now
Try it out