Mean skin temperature in warm humid climates.

Mean skin temperature (Tsk) was measured in 24 subjects during experiments in a climatic chamber. Three conditions of ambient temperature (Ta = 25.6 degrees, 28.9 degrees and 32.2 degrees C), and three of humidity (relative humidity = 50%, 70% and 90%) were studied. A relationship was established by a linear regression technique. It is valid in the 24 degree-34 degree C range, for air velocity = 0.2 m.s-1, clothing insulation = 0.077 degrees C.m2.w-1 (0.5 clo), metabolic rate = 64 w.m-2 (1.1 met) and radiant temperature = air temperature. In these conditions Tsk = 28.125 + 0.021 Pw + 0.210 Ta (Pw: ambient water vapour pressure in mb). It shows a small humidity influence. The influences of sex, transition from one condition to the next, and air velocity were also studied. Measurements in Africa confirmed the small influence of humidity. Ethnic life-style differences indicated that a high precision in Tsk determination is difficult to achieve.