Although I carry a space blanket, it is only a very small part of the equation in staying warm on cold wet nights.

Space blankets are "maligned" for this very reason as people have carried them for years and wonder why these blankets offer very little warmth when needed. If you are wearing cold wet clothes, the little heat that your body is giving off is not enough to dry nor warm these clothes....this also does not factor in ambient temperature, wind and humidity. Wrapping yourself in a space blanket may help somewhat but it is no substitute for proper preparation of shelter.

To test this, go out in the backyard when it is cold and raining and ensue you have with wet clothes on. Wrap yourself in a space blanket and spend the night with it and nothing else for shelter. Sure you will probably survive (which is the ultimate goal) however I can guarantee that you will not be warm and will of spent a very miserable night.