Temperature response (-5 to +60 °C) of effective (ΔF/F_m’) and maximum (F_v/F_m) quantum yield of PSII was assessed in temperate and tropical plants in a comparative eco-physiological approach. Besides thermal limits, optimum temperatures (T_opt) and optimum, sub- and supraoptimal temperature ranges were assessed. The temperature response of ΔF/F_m’ followed a distinct optimum curve. T_opt was higher by 8 K in tropical (28.9 °C) vs. temperate (20.9 °C) plants, ranging from 23.5 to 39.5 °C (16 K) and 9.8 to 33.3 °C (23.7 K), respectively, matching with growth temperature. T_opt increased with increasing irradiation intensity (Musa sp. 0.3 K/100 µmol photons m^-2 s^-1). The suboptimal temperature range was much larger (25.4 K) in tropical than in temperate species (16.8 K). Frost damage commenced in tropical species close to ice nucleation (LT₁₀ -1.9 °C), and in temperate plants at -7.0 °C (LT₁₀). The supraoptimal temperature range was narrower (12.0-12.7 K). The threshold for supraoptimal temperatures was 39.5 °C in tropical and 33 °C in temperate plants. Heat induced PSII impairment was not observed before 51.5 °C and 45.7 °C in tropical and temperate plants, respectively. In darkness F_v/F_m was unaffected by temperature over more than 40 K. Significant changes occurred only upon ice formation and shortly (3.3-7.3 K) above the heat limit of the optimum range of ΔF/F_m’. Tropical plants, in addition to having significantly different thermal limits of PSII appeared to have a higher optimum temperature but a narrower optimum temperature range than temperate species. Particularly within the broader suboptimal temperature range, tropical plants experienced a more severe reduction of ΔF/F_m’ than temperate species. Temperature response curves of ΔF/F_m’ allow assessing the growth temperature conditions of a leaf via its peculiar thermal adaptation.