Abstract Selective laser melting (SLM) enables the fabrication of complex geometries, however the existing literature provides little experimental data on the effect of geometric complexity, such as lattice structures, on the in-situ temperature field. This research applies a wide-field thermal camera to acquire in-situ temperature data for complex Ti64 SLM lattice structures. This novel data enables fundamental insight into how topology affects thermal flow within SLM lattice structures. Specific findings are presented for temperature field and associated lateral cooling rates as a function of lattice topology and local geometry. This data provides fundamental insight into SLM thermal fields and can be used to validate numerical simulations.