With all the other reviews saying it kept them warm I was worried this would not work for me outside in the summer. After wearing it one day I'm thoroughly impressed at it's ability to keep me cool. Just blowing on my arm while wearing this made my skin cold. The mock turtle neck is great for wearing terrible uniforms made of plastic (or at least feel that way) and I think may make wearing a bullet proof vest in the summer far more tolerable. Fits nice and snug but isn't super tight around the neck. All in all I have a feeling it will be great in the summer and am ordering a second one.