Drinking alcohol can decrease body temperature. According to studies over the years, while alcohol may seem like the perfect cold-weather beverage because it creates a sensation of warmth, it actually decreases core body temperature regardless of the temperature outside and increases the risk of hypothermia. The normal process that makes us feel cold occurs when blood flows away from the skin and into the organs, which increases core body temperature. Alcohol reverses this process, increasing the flow of blood to the skin and setting off a sharp drop in body temperature.

Source: NY Times