The volume of out migration has been increasing due to the consequences of the improvement of communication that facilitate people to move. In the past, the majority of studies were mostly interested in the migration process from rural to urban areas. Several studies have tried to explain some relationship between economic factors and the out migration rate. However, there are very few of them that have suggested to look at the effects of drought or an uncertain water source on out migration. All of those studies are descriptive research and could not prove issues that are related to water shortages. Therefore, this study focuses on the influence of water shortages on the out-migration rate. The area of investigation is the Northeastern region of Thailand, in 1994. The study uses 2 secondary data sources. One source comes from the data base survey at the village level by the Department of Community Development, Ministry of Interior. Other source comes from the meteorological data by the Department of Meteorology, Ministry of Communications. The unit of analysis is the sub-district level. The total sample consists of 2,584 sub-districts. The results show that humidity level has an influence on the out migration rate. The imbalance of humidity level for both the ground area and the air, have effects on the migration rate, and push people to migrate out. This rate is also affected by the amount of sufficient of water for agricultural purposes which is measured by annual rainfall data. The spacing of days without rainfall have an effect on the out migration rate as well. In addition, the poverty of the household, the arable farmland, and the development level of the areas have influences on out migration rate. Another migration factor is that when there is a high number of dependents in the household, there will be a high rate of out migration. When the areas have arable farmland, there will be a high out migration rate as well. This study shows the importance of including water shortages in research on migration.