Silk is seen as a traditional spring and summer fabric. However, it is the world's best insulator. So, unless the weave is very open, it is HOT. I have no problem wearing something made from, or made with silk in colder months.
Cashmere can be very light and comfortable in hotter months. I have a sky blue SC that is 100% cashmere and the color says SS, although you could probably wing it in FW in the warmer climes, like where I live.