A heat exchanger includes a plurality of first and second fluid passages. The first fluid passages are defined by a pair of opposing first fluid passage walls and a plurality of first fluid diverters disposed between the first fluid passages walls. The second fluid passages are defined by a pair of opposing second fluid passage walls and a plurality of second fluid diverters disposed between the second fluid passage walls. The second fluid diverters include a body portion and a leading edge portion. The first fluid passage walls form a first fluid leading edge that extends upstream of the leading edge portion of the second fluid diverters. The second fluid passages extend in a direction perpendicular to the direction of the first fluid passages.