A fin and a heat exchanger having the fin, wherein the fin includes a sheet body. The sheet body includes a plurality of cooling sheet units arranged along a longitudinal direction of the sheet body. Each cooling sheet unit includes a windward zone, a main heat exchange zone and a leeward zone arranged along a transverse direction of the sheet body. The windward zones of adjacent cooling sheet units are connected to each other. A flat tube groove extends between the leeward zone and the main heat exchange zone of one of the adjacent cooling sheet units and the leeward zone and the main heat exchange zone of the other of the adjacent cooling sheet units. Each cooling sheet unit is provided with a plurality of protrusions spaced apart from each other.