In this study,using the northern Indian Ocean storms data collected since 1972 and released by JTWC,along with NCEP/NCAR monthly reanalysis data and JMA mean monthly SST data,we analyzed the relationship between the early summer storm activity in the Bay of Bengal and the previous Indian Ocean SST.The results show that the TS activity in April and May of the Bay of Bengal and the SST of the Indian Ocean to the west of Australia have a significant negative correlation,namely the outbreak time of TS in the Bay of Bengal is late or the TS does not occur when the SST in the key areas is high.In addition,when the SST of the important areas is low,there are two scenarios for storm activity.If the Indian Ocean SST north of 30°S is slightly cold (warm) and that of the southeast and southwest Indian Ocean is slightly warm (cold),then the early summer TS appears less frequently or not at all (multiple and early).Further analysis shows that the local circulation changes caused by the high (low) SST in the key area,i.e.the Indian Ocean,leads to the weak (strong) Maschlin high and weak (strong) transequatorial current in the Eastern Hemisphere,which are likely the main reasons for the occurrence time of TS being late (early) and the TS frequency being lower (higher) in early summer.Moreover,when the Somali-equatorial flow and the New Guinea-equatorial airflow undergo weak antipodean synergistic changes,there is a better indication of TS in the Bay of Bengal.