Hello and welcome from Houston, TX!

My preference is to go with the 16 oz, but you will find those here that like the 13. The 16 oz will hold the pleats longer than a lighter weight. Because you are from the NE, I would say that a 16 oz is more versatile for year-round wear than a 13 oz. I wear my 16 oz kilts in the heat and humidity of a Houston summer and they are warm enough for most winters. I do have a 13 oz great kilt, which I only wear once a year in October or November.