The delayed onset of the monsoon coupled with the developing cyclone over the Arabian Sea have resulted in a 45% deficit in rainfall across the country, according to data from the India Meteorological Department (IMD).The country has so far received only 25.8 mm of rain, against the average 46.6 mm expected by June 12.This year, the monsoon hit Kerala seven days later than usual on June 8. A day later, a low-pressure system developed over the Arabian Sea, which intensified into the severe cyclonic storm Vayu that is likely to make landfall in Gujarat on Thursday afternoon.The cyclonic system pulled in the moisture-rich westerly winds, halting the advancement of the monsoon. This year, India experienced its second driest pre-monsoon season in 65 years. Even with cyclone Vayu bringing rain to coastal areas of Kerala, Karnataka, Maharashtra, Goa, and Gujarat, the deficiency is unlikely to be made up in June.By this time, the monsoon usually covers the whole of Maharashtra on the west coast, parts of Chhattisgarh and Odisha in the interior of India, and almost entire West Bengal, North-eastern states and parts of Bihar and Jharkhand towards east India.“Monsoon activity will pick up only after cyclone Vayu dissipates completely. Even then, the progress of the monsoon across the country will depend on how the Bay of Bengal branch of the monsoon picks up. However, a 45% deficiency is quite large and even though it is just June 12, it is unlikely the deficiency will be covered up by June-end,” said K Sathi Devi, a senior scientist at IMD. By June 10, the monsoon usually covers up to the entire Maharashtra on the west coast, bits of Chhattisgarh and Odisha in the interior of India, and almost entire West Bengal, the north eastern states and parts of Bihar and Jharkhand towards East India. However, under the influence of cyclone Vayu, the monsoon has covered just the southern tip of the Indian peninsula, including most of Kerala and parts of Tamil Nadu and a bit of Manipur and Mizoram in the east, till date. Private weather forecaster Skymet said the rainfall deficit in June will likely be 30%, on account of the El Nino effect. The IMD has predicted a near “normal” monsoon this year, reaching up to 96% of the long period average or a 50-year average. So far, the highest deficiency in rainfall has been in Delhi (100%), Dadra and Nagar Haveli (99%), and Gujarat (98%).Gujarat has received only 0.4 mm of rainfall as compared to 19.7 mm it usually receives. Cyclone Vayu is predicted to bring extremely heavy rainfall to Saurashtra and Kutch in Gujarat on Thursday.