Measurements of the per-slat heat transfer coefficient were made for an array of co-planar slat-like surfaces which face upstream into an oncoming flow. The flow washes over the slats as it passes into slot-like gaps between the slats. The experiments were performed for four different slat-slot configurations characterized by the ratio of the slot width to the slat width, and the slot Reynolds number was varied by more than an order of magnitude. Auxiliary experiments encompassing flow visualization and variations of the number of slots were carried out to demonstrate that the results are not influenced by end effects and by the finite number of slots employed. It was found that the dependence of the Nusselt number on the Reynolds number was the same for all of the array configurations investigated and that the influence of the array geometry was very well represented by a power law. This led to the global correlation Nup=1.19 Re0.465 Pr0.375 (P/W)1/4 from which the RMS deviation of the data was only 1.1%.