India, June 21 -- The onset of monsoon in the national capital is likely to be delayed, weather experts said on Saturday, citing the slow progress of the system that is yet to cover parts of the country such as Mumbai, where its normal date of arrival is June 8.

They clarified that the recent spells of rain and thundershowers --- more are expected in coming days --- are not part of the monsoons; they are instead an outcome of western disturbances.

In a typical year, the rains arrive in the national capital around June 27 -- but this year, that arrival may happen well into July.

"For the monsoon to progress, there should be a weather system developing over the Bay of Bengal, to pull the monsoon from the Arabian Sea. This push and pull s...