This study describes the spatial and temporal variations in the physiologic climate of Nigeria for 1951-2009 in terms of effective temperature (ET), temperature-humidity index (THI), relative strain index (RSI) and perception of 3,600 sampled populations. The main hypotheses are that (i) the existing vegetation-based ecological region could adequately elucidate the physiologic climate of the country, and (ii) physiologic stress has significantly increased over the years (1951-2009). Trends and changes in the selected indices (ET, THI and RSI) were examined over two time slices: 1951-1980 and 1981-2009. The results show that (1) the montane region was the most comfortable physiologic climate in Nigeria, and the regions around the Rivers Niger and Benue troughs were the most uncomfortable in most parts of the year, (2) physiologic stress in most parts of Nigeria has significantly increased in 1981-2009 over 1951-1980 (p ≤ 0.05), (3) coping strategies to the uncomfortably hot and cold climate in Nigeria are limited to dressing mode, clothing materials and use of air conditioners or fan, (4) ET, THI and RSI results could be similar, and complementary; but each is with its strengths and weaknesses for annual or seasonal representations, which the others complemented for the interpretation of the physiologic climate of Nigeria. The study concluded that the relationship between the ecological classification of Nigeria and physiologic climate is rather complex, and the former could not elucidate the latter. The study cited inadequate meteorological data, especially on wind chill, and health records as limiting factors of studies on the Nigerian physiologic climates and the effect of extreme thermal conditions on the people.