This paper examines how change in rainy season induces adaptation strategy among farmers and affects rice production using recently collected household data from seven provinces in Indonesia. The data demonstrate delays in the perceived onset of rainy season and increased uncertainty in rainfall pattern in the region. Empirical analysis shows that (i) delay in the onset significantly decreases land productivity growth in rice production; one month delay offsets the average growth observed in 1999-2007, (ii) irrigation share significantly explains the growth of land productivity, and (iii) farmers change planting timing in response to delays in the onset of rainy season (water availability). Our results show that delays in rainfall decrease returns to irrigation infrastructure. It is also found that individual-level variations in the perceived changes of the onset explain the extent to which such an adaptation strategy is taken as a measure to respond to climate change.