New Delhi: An intense heatwave scorched parts of north India on Sunday with places in Delhi and Uttar Pradesh recording 49 degrees Celsius and above while the weather office has warned of heavy rainfall across Kerala and sounded a red alert for five districts.

In Delhi, the Safdarjung observatory recorded 45.6 degrees Celsius while two weather stations at Mungeshpur in northwest Delhi and Najafgarh in southwest Delhi reported 49.2 and 49.1 degrees Celsius, respectively.

The temperature at Safdarjung was the highest this season.

Banda district in Uttar Pradesh's Bundelkhand region recorded the maximum day temperature of 49 degrees Celsius, the highest in the state.

As per the India Meteorological Department (IMD) data, this was the highest-ever temperature recorded in Banda in May. The previous maximum temperature in the district was 48.8 deg Celsius on May 31, 1994.

Churu and Pilani in Rajasthan reported maximum temperatures of 47.9 and 47.7 degrees Celsius, respectively, followed by Sri Ganganagar and Jhansi (47.6), Narnaul (47.5), Khajuraho and Nowgong (47.4) and Hissar (47.2), the IMD said.

The weather office said the maximum temperature was markedly above normal (5.1 degrees or more) at several places in Himachal Pradesh, Haryana, Delhi, Jammu, Kashmir, Ladakh, Gilgit-Baltistan, Uttarakhand, Punjab, and Bihar.

The IMD said the maximum temperatures were appreciably above normal (3.1deg C to 5.0 deg C) at many places in West Uttar Pradesh, East Uttar Pradesh, East Madhya Pradesh.

The weather office said under the influence of a western disturbance, dust storm and thunderstorm were expected over northern parts of Punjab and Haryana on Monday, while a mild dust storm was likely over remaining parts of Punjab, Haryana, west Uttar Pradesh and at isolated pockets of Delhi NCR.

While north India braved the high temperatures, most parts of the southern peninsula experienced heavy rainfall with Kerala and Lakshadweep reporting heavy spells of 52.2 mm and 57.7 mm on Sunday, respectively.

The IMD had issued a warning of heavy rainfall across Kerala and sounded a red alert for five districts Ernakulam, Idukki, Thrissur, Malappuram and Kozhikode.

According to the weather office, Ernakulam had reported 122.2 mm rainfall on Sunday, which was 13 times the normal of 8.3 mm for the day. Kollam reported 113.6 mm rain followed by Thiruvananthapuram (109.1 mm), Alappuzha (97.4 mm), Pattanamita (85.1 mm), Thrissur (81.6 mm) and Kottayam (74.3 mm).

The weather office has forecast early onset of monsoon over Kerala by May 27, which is five days before the normal date of June 1.

"Southwest Monsoon is likely to advance into South Andaman Sea, Nicobar Islands and the adjoining Southeast Bay of Bengal during next 24 hours," the weather office said.