Abstract Midlatitude oceans are characterized by vigorous turbulent heat flux (THF) from the ocean to the atmosphere. While the influence of sub‐weekly, synoptic‐scale atmospheric eddies on short‐term THF variability is well‐documented, their long‐term, ‘rectified’ effect on air‐sea interactions remains poorly understood. Here we present a global assessment of these synoptic‐scale eddies’ effects on climatological‐mean and interannual variability of THF. We demonstrate that synoptic‐scale atmospheric fluctuations enhance annual‐mean climatological upward THF almost globally, primarily by increasing wind speed. This enhancement is maximized around midlatitude oceanic frontal zones, reaching ∼30% of the climatology. In addition, atmospheric eddies amplify interannual THF variability in mid‐ and high‐latitudes although suppressing the variability in low‐latitudes. Our findings underscore the importance of synoptic‐scale atmospheric eddies for long‐term air‐sea interactions, especially in midlatitudes, and the need to appropriately represent storm‐tracks in climate models to obtain realistic mean states.