The present study experimentally investigated streaky structures of wall temperature in the free-stream turbulence transition scenario. An infrared thermographic camera acquired time series data of the wall-temperature distribution on a flat plate employing a heating section made of 5 \(\upmu \) m titanium foil installed in a wind tunnel with a turbulence grid. Streamwise-oriented wall-temperature streaks collapsed with increasing free-stream Reynolds number. High- and low-temperature streaks are discussed in comparison with velocity streaks reported in previous studies.