UHF profiler observations of lower tropospheric winds at San Crist¿bal in Ecuador's Gal¿pagos Islands commenced in October 1994. The available data give a detailed picture of the lower troposphere's annual cycle over this portion of the East Pacific cold tongue. The profiler tracks the low-level southerly wind maximum from its weakest state in austral summer, when it may briefly rise above 1 km, to its strongest state mid-year, when it is often found below 400 m. The profiler operated during much of the 1997--98 El Ni¿o and gives us an unprecedented look at dramatic changes in the flow over the cold tongue during a warm event. The seasonal deepening of the low-level flow was enhanced as the ITCZ moved into the Southern Hemisphere for a few months and the lower tropospheric winds became northerly. ¿ 2000 American Geophysical Union