Tires: Tires, trail blazer, adice

Question
About one year ago I bought 4 Michelin x-radials for my 2002 trail Blazer, we didn't real could weather after i bought them or I never drove it in real could weather, however in Nov it got down to around 20 degrees and I drove it on the open hoghway and the raod noise was bad, after it warmed up it went away, I cared it back to Sams aand they said the tires were defated down to 26 lbs and all four were out of balance( don't under stand that this is used for casual driving not off road or rough driving), so the flated the tires and balanced with roatation and said that should take care of the problem if not let them know, yesterday it was down to the 20's and it down it , this is the first time since Nov i've driven it on open highway with it that could and again after about 12 moles we stopped and ate when we came back home there was no noise. I went to Sams and they said they have never seen this and are willing to do what ever I want , I'm going back there Tuesday morning , and they are going to call the company to if they have heard of this before, by the way I checked the tire pressure yesterday when we got back home and they all had 35 degrees, it came with goodrich in it. Thanks for the adice in advance

Answer
First, I think there is absolutely nothing wrong.

When things are cold, they transmit vibrations more easily(and noise is a high frequency vibration) because the molecules are closer together.  

Also the way the structure of your vehicle reacts to vibration changes when it is cold - it transmits higher frequencies more readily.

So you should expect more noise when the temperature gets cold.