A convective underbody blanket has a head portion and a body portion. Provided at the head portion is a non-inflatable head area surrounded by a channel that has arranged thereat at least one row of air apertures that are oriented toward the non- inflatable head area when the channel is inflated. At the body portion there is provided a non-inflatable body area. Along each longitudinal side of the body area there is at least one longitudinal channel. Each of the longitudinal channels is in fluid communication with the channel that surrounds the non-inflatable head area. The longitudinal channels that sandwich the non-inflatable body area extend substantially along the length of the non- inflatable body area and are in fluid communication with each other by way of a cross channel formed at the foot end of the blanket. The configuration of the blanket allows air input to the blanket to be circulated through the various channels, so that the heated air output from the different rows of apertures formed at the various channels has substantially the same temperature. The different rows of apertures may be provided at different areas along the blanket.
