The effects of wind and rain on exercising humans have not been fully investigated in the field of sports science. The purpose of this study was to investigate the characteristics of thermoregulation and cardiovascular-respiratory responses during exercise in a climate chamber that allowed control of wind and rain. Seven healthy males performed treadmill running at 70%VO_2max for 30 min under three conditions (CON, control ; WIND, wind only; WIND&RAIN, both wind and rain). The temperature was 27.0℃ under the three conditions. Relative humidity was 60%RH except under the WIND&RAIN condition (100%RH under WIND&RAIN condition). The wind velocity corresponded to running velocity in the open air and the precipitation was 90 L/h. Under the WIND&RAIN condition, both body trunk and extremities skin temperature (T_sk) showed a clear decrease for the first 5 minutes after the start of running, and was significantly lower during the running period than under the other two conditions (p<0.05). Rectal temperature (T_re) did not differ significantly among the three conditions. An interaction was observed between conditions and time in terms of minute ventilation (VE) (p<0.05). Under WIND and WIND&RAIN conditions, VE was higher than under CON condition while running. Oxygen consumption, heart rate and respiratory exchange ratio did not differ significantly among the three conditions. These results indicate that wind and rain in a natural environmental condition with neutral temperature (27.0℃), cause a decline in T_sk, and may become factors that influence performance, similarly to temperature and humidity.