A heatwave alert was issued for Kolhan and Santhal Paragana divisions of Jharkhand for three days from April 19.
The districts which will be affected are East Singhbhum, West Singhbhum, Seraikela-Kharsawan, Dumka, Pakur, Godda and Sahibganj, the weather office said on Wednesday.
At least eight districts recorded day temperatures of above 40 degrees Celsius, and it is likely to increase further by 2-3 notches over the next three days, it said.
Seraikela recorded the day's highest at 43 degrees Celsius, followed by Godda at 42.5 degrees Celsius. Pakur was at 41.5 degrees Celsius, while Daltonganj district was sizzling at 40.2 degrees Celsius, it added.
Jamshedpur in East Singhbhum district was at 41.5 degrees Celsius, and Chaibasa in West Singhbhum recorded 41.6 degrees Celsius.
In state capital Ranchi, the mercury rose to 36.8 degrees Celsius.
Ranchi Meteorological Centre in-charge Abhishek Anand said there was no significant synoptic confiding over Jharkhand and only north-westerly to westerly surface winds were prevailing, resulting in the mercury rising.
People were advised to avoid going out between 11 am and 4 pm and to stay hydrated.
