To establish SEASAT sensor wind measuring capabilities, the best possible surface wind were needed. Fortunately, during the 99 days of SEASAT operation, two large scale experiments were conducted. The first, the Gulf of Alaska Experiment (GOASEX), was directed at obtaining data in conjunction with SEASAT. The second, the Joint Air Sea Interaction Experiment (JASIN), was an independent and much more comprehensive air and sea investigation and fortunately provided excellent comparison data for SEASAT. In addition, several storms provided good qualitative comparison windfields. since the windfields have been developed independently of satellite-determined winds, this paper deals only with the surface wind analysis and its accuracy. A subsequent paper will use these results to discuss the satellite sensor predictions compared with these data sets.