In Latvia to perform COVID-19 tests as well as for temporary shelters in case of a local disease outbreak the persons were located in special tents. Such practice was not only performed locally but also in other countries like the USA, UK, Russia, etc. The wide usage of tents was possible as the outbreak happened during the warm period of the year. At the same time, the indoor climate of tents can be quite unbearable during the warm summer days. Also, the situation was not getting better as fast as the prognosis, and the crisis was still ongoing during the winter period. Therefore, to test the thermal comfort of such temporary shelter’s measurements were performed. The thermal comfort was measured in a tent from 27th May to 28th September 2020. The data was logged with three different measuring devices inside of the shelter as well as outside air parameters like temperature and solar radiation was logged. The results show the rapidly changing indoor temperature which reaches 40°C during the daytime and falls to 10°C at night. The data of the globe thermometer to analyze the influence of radiation from tent canvas was also studied and showed that there is no noticeable heat radiation from external walls. The PMV measurements showed that the thermal comfort is very low as the PMV values were outside the range of -1 to 1 for 57% of the time. The influence of the precipitation was also noted, and the results showed that the adiabatic cooling effect is very variable but in general does not noticeably change the indoor temperature, the average temperature decrease was only 1 °C, but for a specific case it reached 10°C.