Enhanced heat transfer surfaces have complex flow and thermal boundary layers. The temperature profile of the fluid away from a surface is a vital part of evaluating heat transfer effectiveness. This paper reports temperature distributions in turbulent water flow recorded by a Planar Laser-Induced Fluorescence (PLIF) system. A solution of water and Rhodamine B with a concentration of 1mg/L flows through a duct that has a micro-finned (fins of about 0.3 mm in size) surface. The illumination source is a Nd: YAG laser (wavelength = 532 nm). The study obtained average temperature distribution curves. The impact of changing the flow rate was investigated by testing the flowing with Reynolds numbers 28200, 21200, and 13800 in the 13 mm by 13mm duct. The conclusion is that PLIF can show differences in temperature profiles, but that near-wall effects require special attention and techniques to resolve accurately with PLIF.