Time management governs climate resilience and productivity in the coupled rice-wheat cropping systems of eastern India

India must increase wheat production by ~30% by 2050, largely through intensification in eastern India where productivity is low. Using extensive on-farm surveys for rice–wheat systems, satellite time series, and crop simulation, the study shows that wheat sowing date is the dominant determinant of achieved and attainable yields, exceeding other management, soil, and varietal factors. Advancing sowing dates can increase untapped wheat production potential by 69% without trade-offs with rice productivity, irrigation, or profitability. Transformative wheat yield gains in eastern India require managing rice and wheat as a coupled system. Better ‘time-keeping’ of the annual cropping calendar enhances food security, profitability, and climate resilience now and under progressive climate change.