While it does provide protection against wind & water which will help keep you warm, GORE-TEX on its own has no insulating properties. Many GORE-TEX products are a 2 or 3 layer waterproof/breathable fabric without insulation and are considered shell jackets. These were designed like this so you can layer underneath with either a technical fleece or a down/synthetic puffy depending on the warmth you need for that day’s conditions. Some jackets have a GORE-TEX layer and are lined with a down or synthetic insulation layer to add warmth.