Our dance club has no dress code. Keep in mind there is a lot of energetic movement in square dancing, so light weight, comfortable clothing works well.
In the winter, wearing something that can be removed as you warm up from dancing, is a good idea. Shorts and T-shirts, in warmer weather, work just fine.
Shoes that allow you to slide and turn work best, leather soled or some other forgiving material is preferential. Lots of dancers wear cowboy boots, bowling shoes or runners. Whatever works best for you.
We also have special dances where you can dress up more formally if you choose, or go completely crazy!