Some definitions describe heat waves as periods of excessive heat and humidity, which generate the human heat stress due to overheating. For this reason, heat waves can be deadly, and they rank among the world’s top 10 natural disasters. European countries have already experienced some severe heat waves in the 21st century (in 2003, 2006, 2010 and 2011) and climate models predict an increase in the frequency and intensity of mega heat waves in the years to come. That is why, case studies may be very important in the reconstruction of climate models. This paperworks debates on the synoptic conditions that generated the heat wave affecting Romania’s territory on 14-16 July 2011. Moreover, it presents the distribution and evolution of air-temperatures which, in combination with high humidity, contributed significantly to the discomfort people felt during the heat wave. This was quantitatively assessed by the Temperature-Humidity Index (THI) and UV Index, with corresponding values given below.