This study evaluates nextGEMS Earth system models (ESMs) with storm-resolving spatial scales. Taking advantage of the fine-scale resolution of nextGEMS ESMs, we compare their simulations of Southeast Asian climate and weather systems–strongly influenced by complex sea-land contrasts–to observations and to several CMIP6-class ESMs with coarser horizontal resolution. The nextGEMS ESMs realistically reproduce the sharp structure and seasonal development of the South China Sea cold sea surface temperature (SST) during the winter monsoon season, while most of the selected CMIP6 ESMs fail to simulate these cold SST characteristics. The nextGEMS ESMs also represent the climatological precipitation pattern well. On shorter time scales, they capture the characteristics of monsoon cold surges and Borneo vortices well. Furthermore, dry spells in Southeast Asia are assessed. In particular, nextGEMS ESMs can simulate the increase in winter dry days around the equator during intense El Niño events. Because Southeast Asia is one of the regions most vulnerable to climate change in terms of wet and dry spells, we highlight the potential benefits of kilometer-scale ESMs for producing climate predictions and assessing climate projections in marginal sea areas.