Squall has four sets of clothing through-out the game(unless you are counting the space-suit); theres the Balamb uniform, the SeeD uniform, his regular clothes, and what he wears as a child. Here is a fairly detailed description, along with a picture, of each outfit.

Casual This is the outfit that Squall wears for pretty much all of FFVIII. It consists mainly of a jacket, T-shirt, pants, and boots. The jacket is black, long-sleeved, and appears to be made of some kind of leather. On it's neck is a bushy, furry, white collar which looks as though it could have come from some kind of animal. Underneath the jacket, Squall is wearing a snug white v-neck T-shirt. His pants are black and fairly baggy; comfortable looking. Squall's boots are black with little metal clasps on the sides, and are always tucked under his pants. Around his waist, Squall exhibits three belts: a thin black one with a silver buckle, worn like a normal belt, and two others worn criss-crossing each other across his hips. The first of these criss-crossing belts is brownish/red with round silver emblems and a large silver buckle. The second one is black with a small silver buckle buckle, and silver circles embedded all along it's length. Around his right leg, there are three black straps secured with silver fasteners, and on his hands, he is wearing black leather gloves.

SeeD Uniform The SeeD uniform is what Squall wears to the dance, and it is really the only formal thing he wears through-out all of Final Fantasy VIII. It consists of a black jacket with yellow trim, and a golden chain that connects one side of his collar to the other. There is a golden yellow design embedded on the front shoulders and collar. On the back, however, the shoulders and collar are navy blue. The SeeD jacket is much longer than his regular one, going down to just past the start of his legs. Overlapping the jacket is a thick black belt worn normally with a silver fastener. Once again his pants are black and fairly baggy but unlike his usual pants, these ones are tucked into his boots, which also happen to be black.

Balamb Uniform This is Squall's school uniform before he becomes a SeeD. It is navy blue with bronze lining, consisting of a jacket, T-Shirt, pants, and boots. Like the Seed Uniform, there is a bronze design embedded onto the front shoulders of the jacket. He wears this unzipped to expose a white v-neck T-shirt and his favourite necklace, Griever. His pants and boots, like the jacket, are also navy blue.

Child Outfit As a child, Squall is seen in a fairly baggy yellow T-shirt decorated with two blue horizontal stripes. It has a v-neck, and looks as though it would be very comfortable for a little boy like him to wear. His pants are a very dark shade of blue and are incredibly baggy, similar in appearance to those of a snowboarder. His look is completed with a small pair of round black shoes. It is quite a typical outfit for a boy his age to wear.

Griever-Related I know this isn't an outfit, but considering how much Griever stuff Squall has, the Griever items deserve a whole section to themselves. The picture to your right is a necklace that Squall wears at all times, a silver chain with a Griever symbol on the end of it. Although they aren't in the picture, he also wears a Griever ring, and has a Griever keychain attached to the handle of his gunblade.