NEW DELHI - India's annual monsoon covered the entire country on Saturday, six days earlier than usual, the state-run weather office said, but rain totals are 5% below average so far this season.

The monsoon, critical for farm output and economic growth in the world's second-most populous country, arrived on the coast of the southern Kerala state on May 29, a couple of days ahead of usual, yet after a promising start the rains gradually tapered off, clocking an 8% deficit in June.

Last month's patchy rains slowed the planting of rice, an essential summer crop.

India's rice farmers have planted 4.3 million hectares with the grain so far this season, down 27% from the same period last year.

The progress of the monsoon, which delivers about 70% of the country's annual rainfall, is crucial for rice output and exports from India, the world's biggest exporter of the grain.

Poor monsoon rains would further delay rice planting, stunt the crop and cut yields, leading to a drawdown in state inventories that would trigger export curbs to ensure sufficient supplies for the country's 1.4 billion people.

India is likely to receive monsoon rainfall between 94% and 106% of the long-term average in July, the most crucial month for planting rice and a host of other summer crops such as corn, cotton, soybean and sugarcane, the India Meteorological Department had said on Friday.

The weather office defines average, or normal, rainfall as between 96% and 104% of a 50-year average of 87 cm (35 inches) for the entire four-month season beginning in June. Rain totals or between 90% and 96% are considered below average.

Bountiful monsoon rains in July would ease concerns about the output of summer crops, promising higher incomes in the countryside where most Indians live. As almost half of the country's farmland lacks irrigation, Indian farmers depend on the monsoon.

The farm sector employs more than half of the country's population and accounts for nearly 15% of India's $2.7 trillion economy, Asia's third-biggest.

(Reporting by Mayank Bhardwaj; Editing by David Holmes)