Chandrapur in Maharashtra was the hottest place in the country on Wednesday as mercury rose to 47.8 degrees Celsius, it said.
The day temperature in Delhi on Wednesday was 42 degrees Celsius, it said.
"Temperature in Delhi will cross 46 degrees Celsius soon since there is no pre-monsoon activity and whatever western disturbances are there, are feeble. There are no chances of rains. It will keep temperature high for 10-12 days," said Mahesh Palawat, Director at Skymet.
The temperature in Vidarbha's Nagpur and Chandrapur was over 47 degrees Celsius on Wednesday.
According to the India Meteorological Department, heat wave to severe heat wave conditions in many parts are "very likely" to continue over Vidarbha and in some parts of Madhya Pradesh.
Heat wave is also expected at isolated pockets over central Maharashtra, Marathwada, Telangana, Haryana, Chandigarh and Delhi, Rajasthan, Bihar, Jharkhand, Uttar Pradesh, and Odisha during next two-three days.
Meanwhile, thunderstorm and dust storm is expected in some parts of Rajasthan. Also, rains are likely in southern states of Tamil Nadu, Karnataka and Kerala.
The IMD said widespread rainfall was "very likely" over Andaman & Nicobar during the next four days.
"Fairly widespread to widespread rainfall activity with isolated heavy falls very likely to occur over Sub-Himalayan West Bengal & Sikkim and northeastern states from 30 May onwards," it said in a release.
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( With inputs from IANS )