MUMBAI - Crop-nourishing monsoon rains are likely to reach Kerala state on India's southern tip on May 27, five days ahead of the usual time, the country's weather office said on Friday.

"This year, the onset of southwest monsoon over Kerala is likely to be earlier than normal date of onset," the state-run India Meteorological Department said in a statement.

Nearly half of India's farmland has no irrigation and depends on annual June-September rains to grow crops such as rice, corn, cane, cotton and soybeans.

India's weather office said last month the country was expected to get average monsoon rains this year, raising expectations of higher farm output, which is central to the country's economy.

New Delhi defines average, or normal, rainfall as ranging between 96% and 104% of a 50-year average of 87 cm (35 inches)for the four-month season beginning in June.

(Reporting by Rajendra Jadhav; Editing by Alison Williams)