Analysis of optical and physical oceanographic measurements taken during TOGA/COARE show optical and thermohaline anomalies in the presence of rainwater layers. Over 1500 profiles were taken aboard R/V Vickers down to 200 meters providing upwelling and downwelling irradiance data (in 13 spectral wavebands from 340 to 683 nm), CTD variables, beam transmission and chlorophyll fluorescence. Two optical rain gauges mounted on the bow of the ship provided continuous time series of rainfall rates. Salinity profiles taken during strong rain events show layers of relatively freshwater forming at the sea surface and extending down as far as 20 meters. The salinity deficit was as low as 0.7 psu. Temperature / salinity characteristics of these layers do not exhibit simple mixing lines between the ocean and rainwater endmembers. It is proposed that differential mixing of heat and salt might account for the observed characteristics, but high heat flux out of the rain layers may also be responsible. At times the rainwater layers exhibit increased values of the beam attenuation coefficient at 660 nm during episodes of light winds (< 7 m/s). The increase in beam attenuation may result from index of refraction changes caused at the surface by the input of fresh and relatively cold rainwater.