AbstractThe relationship between the aerial temperature, distribution pattern during the crop growth period, accumulated heat units and sunshine hours at different growth phases of sorghum (Co 25), and the growth parameters of the crop, sown on weekly intervals from January 29, 1986 to March, 1986 was studied at Coimbatore, India. Number of days for completion of germination, height of plant, leaf area index, grain, straw and total dry matter yield were found to be related to the sunshine hours. Grain and straw yield were negatively related with the heat units accumulated at the seeding stage. Grain yield alone was positively related to accumulated heat untis at flowering stage, while grain and straw yield were not related with heat units at growth, bootleg and maturity stage. Total accumulated heat units during the entire growth period of the crop was positively related to the grain and straw yield. Treatmental variations were significant for grain, straw, total dry matter production and other growth parameters except tiller numbers. An early cooler temperature followed by a warmer temperature during flowering, maturity phases are crucial for higher grain, straw and dry matter production.