The Ideal Temperature for Lemon to Assimilate CO2 and Develop its Leaves is 25 to 30°C

In lemon cultivation, maximum CO2 assimilation is achieved between 25 and 30 °C, temperatures considered optimal for photosynthesis and leaf development. However, this assimilation decreases significantly when these ranges are exceeded.

Source : Chaves-Barrantes, N. F., & Gutiérrez-Soto, M. V. (2017). Responses to heat stress in crops. I. Molecular, biochemical, and physiological aspects. Mesoamerican Agronomy, Costa Rica, 28(1), 237-253.