Belt squeel is normally caused by the pulley moving faster than the belt. On cold days the belt is not pliable and can slip and the noise starts. So, it's important to look at the belt for any damage at all and make sure it's aligned and tensioned correctly.
Belts do glaze. When the belt's cold and flying around the pulley at a bizillion miles an hour it will squeel as the belt can't quite keep up with the pulley.... which adds to more glazing. As the friction heats the belt it softens, stretches a bit, and the squeel goes away... like when you get sick and tired of the squeel and "goose" the engine and like magic, silence occurs. You can brake down glase with a little sandpaper applied to the underside of the belt as it's moving, but bear in mind... it's your fingers... count them when you're done.
Belt dressing is now a spray, not a compound stick. I've never found it to help a great deal except to remove oil that's found it's way to the pulley. I don't think you can buy the old stick stuff any more for liability reasons... and the spray just ain't as good as the stick. It tends to fly off a few seconds after it's applied. I would not trust it exeept as a degreaser.
If the tension and the belt are in good shape, about the only thing left is the pulleys. Check to make sure the pulleys are aligned properly with one anohter. Look at the pulleys to see if the are worn and could capture a belt. A pulley can be "dished" and as the "V" of the pulley widens at the top it lets the belt slide furhter down the groove untill the pulley caputers the belt. If the belt is captured it tends to be pinched, halts, and glazes while the pulley turns. The result is a squeeling belt.
There is also a load factor that's difficult to determine. The surface of the belt and pulley can only provide so-much friction/grab and if the load of, say an alternator, is too high then the belt may also suffer and glaze over. This is a rarity, but does happen and should be considered.
Barring that, then I'd bet the problem is the cold causing the problems. Try a little talc applied to the uderside of the belt. I'm sure others will chime in with a fix as well.