Suicide is a stark indicator of human hardship, yet the causes of these deaths remain understudied, particularly in developing countries. This analysis of India, where one fifth of the world’s suicides occur, demonstrates that the climate, particularly temperature, has strong influence over a growing suicide epidemic. With 47 y of suicide records and climate data, I show that high temperatures increase suicide rates, but only during India’s growing season, when heat also reduces crop yields. My results are consistent with widely cited theories of economic suicide in India.