What would make a car squeal for about 30 seconds when you start it but only after it had been sitting in the sun?

IF IS ONE OF THOSE HIGH PITCH SQUEALING SOUNDS IT MAY BE DO TO A FAUTLY/LOOSE BELT. IT USUALLY SOUND WHEN THE CAR IS TURN ON BUT AS IT ROTATES IT PICKS UP SPEED AND IT STOP THE SQUEALING. WELL THE SUN PART COULD BE DUE TO THE HEAT IT DRIES UP YOUR BELT AND CAUSE TO SQUEAL/SLIP. TRY PRESSING ON YOUR BELTS THEY SHOULD'NT MOVE MORE THAN HALF AN INCH.CHECK YOUR MANUAL FOR YOUR SPECS.