Personal protective clothing (PPC) is required in a variety of sectors and is important from both a safety and a thermal management standpoint. Materials used in PPC play a key role in protection. Extensive research has been conducted on the risk variables that lead to thermal load and the corresponding functional properties of PPC, particularly in high-risk categories. In contrast, despite the fact that employees who wear this type of PPC constitute a major fraction of the industrial workforce, relatively little study has been undertaken on PPC materials in low-risk categories and their thermal management properties. For this study, four new PPC materials were specifically engineered to have improved thermal attributes and were compared with four existing PPC materials of equivalent protection levels, as well as four summer-season civilian materials, to determine the most suitable materials for use in hot outdoor environments. We investigated and compared the thermal management properties of these novel materials, including liquid moisture transfer, thermal and water vapor resistance, and air permeability, to those of current materials used in low-risk PPC as well as civilian materials. The results demonstrated that the new PPC materials had improved thermal and vapor resistance; superior liquid moisture transfer properties; higher air permeability; and were lower in mass and thickness than the existing PPC materials. Furthermore, the new materials compared favorably with the civilian materials in a number of these attributes. The new materials should be included in low-risk PPC designed for use in hot outdoor conditions.