AbstractThe Caribbean Low Level Jet (CLLJ) is shown to be a real and dominant climatological feature of the early summer Caribbean climate. It manifests as an intensification in the trade winds in the western Caribbean basin (70°W–80°W) with an east‐west axis along 15°N. It is confined to heights below 600 mb and has maximum wind speeds approaching 16 m/s near the surface. The study shows that there is variability in the strength and zonal extent of the CLLJ which can be related to zonal SST gradients between the eastern equatorial Pacific and the north tropical and/or equatorial Atlantic. When the gradient is driven by the Pacific (as in an EL Niño event) the CLLJ winds are intensified to the north and in its southwesternmost quadrant. When the winds are driven by the tropical north Atlantic there is uniform wind intensification about the jet axis. The CLLJ is also linked to a precipitation maximum over the near waters and along the Caribbean coast of Central America (up to 16°N) during June and more so, in July. There is evidence of variation at the northern extent of this wet zone depending on the ocean basin forcing the SST gradient. The CLLJ is also linked to moderate drying in the main Caribbean basin. Copyright © 2007 Royal Meteorological Society