Growth and photosynthetic performance were assessed for the Finnish wheat Triticum aestivum L. var. APU under a cool (13/10°C day/night) and a warm (30/25°C day/night) regime. Plants exhibited a certain degree of acclimation to warm growth conditions. This acclimation appeared to involve enhanced performance of both photosystem II and whole-chain electron transport. Enhanced thermal stability of photophosphorylation was also observed in warm-grown plants.