Boron concentrations of coastal North Florida rainfall averaged 8.3, 12, and 7.0 μg l 1 for summer showers, winter frontal activity, and samples collected sequentially during tropical storm Becky, respectively. B/Na ratios were 11¿10-3 and 5¿10-3 in summer and winter samples respectively. Mean calculated B enrichments ENn(B) for summer and winter sample sets were 32 and 11, respectively. A surprisingly constant concentration of 'excess' B above that expected from direct seawater injection of approximately 6 μg l-1 was observed in the sequential Becky samples. The lower winter B/NA ratios, and thus the calculated ENn(B) values, appear related to higher Na concentrations; however, several alternative hypotheses can be advanced to explain the results, including greater particulate sea-salt injection during the winter months, incorporation of soil materials with a B/Na ratio above the seawater value, and possible influences of temperature variation on gaseous B incorporation in rain and evaporation from the sea surface.