Sea surface temperature (SST) estimates were made using data for C37‐39 alkenones analyzed in modern and glacial‐age intervals of sediment cores collected along an east‐west (∼42°N from 125° to 132°W) and a north‐south (41°–33°N) transect of the California Current system (CCS). The prymnesiophyte biomarker results suggest that surface waters warmed...