To sustain food production in the future, the agricultural sector must adapt to changing climate conditions through agronomic means. In the MidiPyrénées (south-western France), maize is the main irrigated crop, and increasing pressure on water resources questions the appropriateness of this crop in the region. In this study, we evaluated the impact of temperature and precipitation changes on the sowing and harvesting period of maize and consequently on the suitability of cultivar earliness to this sowing-harvest window in the future. We ran two models with climate-change scenarios. The first model calculates the days suitable for sowing maize, and the second calculates the days suitable for harvesting. We ran these models with simulated weather data series covering the reference period (1971-2000) and two future periods (2021-2050 and 2071-2100) for the study area. Further, we calculated climatic and agronomic indices to understand the changes in maize sowing days, the maize growing period and suitable earliness choice due to climate change for the two future periods, compared to the reference period. The results showed an increase in thermal time and decrease in rainfall in the future that will influence maize earliness choice and growing period. The trade-off between farmers’ maize earliness choices and suitable maize growing periods will increase in the future. Late-earliness maize cultivars can be cultivated in the future; however, more detailed analysis is needed on irrigation requirements for the changes in cultivar earliness, maize growing period and shift in maize growth stages to cope with climate change.