ideal climatic conditions to grow coffee are related to temperature and rainfall; temperatures in the range of and with rainfall incidence in the range of followed by a dry spell of 2–3 months suit the "arabica" variety. cold temperatures closer to freezing conditions are not suitable to grow coffee. where the rainfall is less than , providing irrigation facilities is essential. in the tropical region of the south indian hills, these conditions prevail leading to coffee plantations flourishing in large numbers. relative humidity for "arabica" ranges 70–80% while for "robusta" it ranges 80–90%.