Implementations of a clothing article with an integrated thermal regulation system are provided. In some implementation, a clothing article with an integrated thermal regulation system may be configured to heat a portion of a wearer's body by transferring heat from a warmer first region of the body (e.g., the calf portion of the leg or wrist portion of the arm) to a cooler second region (e.g., the plantar side of the toes or the dorsal side of the fingers). The transfer of heat is facilitated by a thermally conductive fluid that flows between a first thermal transfer bag in heat exchange contact with the warmer first region of the wearer's body and a second thermal transfer bag that is in heat exchange contact with the cooler second region, the thermal transfer bags being held in position by the clothing article into which they have been integrated.