A fan belt noise come and goes. In the morning it is always there. You drive a few miles and turn off the car, and when you turn the car on again the noise is not there. than later in the day afer the car has been off for a few hours the noise comes back.
If it’s a squeal (you didn’t describe it), since it’s only making the noise when cold I’d want to listen to see if it’s coming from the serpentine belt or the tensioner.
As my friend, mountainbike, implied, it sounds like it is either a loose belt or something related to the belt. First, verify whether the belt tensioner is still doing its job.
If the belt is under the proper tension, then the next suspect would be the bearings in either the tensioner or the idler pulley. 36k miles would be very early for bearing failure in the tensioner or the idler pulley, but I suppose that it is possible.
At 5 years it may be time for a new belt. I’ve had good luck replacing noisy belts with Goodyear Poly-V serpentine belts . I replace mine every 3 or 4 years.