The study material consisted of two models of protective firefighter footwear. The tests were conducted on subjects in a laboratory using an ergometric treadmill. The parameters of footwear microclimate were continuously recorded using T/RH sensors. For the leather footwear, the highest foot temperature was recorded in the 50th minute of the experiment (35.8°C in the dorsal region and 37.3°C in the plantar region) and for the polymer footwear in the 60th minute of the experiment (35.4°C in the dorsal region and 37.0°C in the plantar region). In the leather footwear, the temperature of the air surrounding the feet rose from 31.0°C to 35.4°C, and then declined, but did not return to the initial level during the rest period. In turn, in the polymer footwear, the temperature rose from 29.0 to 34.7°C, and then decreased to 33.7°C following the rest period. The highest relative air humidity was recorded in the polymer footwear (96.6%), while in the leather footwear it amounted to 91%. Testing the dynamics of the microclimate during footwear use provides complete information about changes in the temperature of the skin of the foot and the temperature and relative humidity of the footwear microclimate.