This is not a thermal shirt. Wore it under another shirt this past weekend and it was only low 50s. Still got cold. You can see through it. I have long sleeve cotton T-Shirts that are warmer than this shirt. It is very lightweight and you can easily see through the fabric. Sleeves shortened quite a bit after one wash and dry. So here is the positive; feels good against your skin. the fabric is comfortanle. But for what I paid I feel like I wasted my money.