During Rohini Nakshara, the distance between the sun and the earth gets reduced significantly resulting in days and nights getting hotter than the rest of summer months comparatively

Just a day before Nautapa, beginning from May 25, the maximum temperature of Rajasthan’s Churu and Ganganagar on Sunday recorded 47 degrees Celsius, hottest in the country.  Nautapa is considered hottest days of the summer season when the sun enters into the Rohini Nakshatra. The next nine days beginning from Monday, could be hottest days of the season.

During Rohini Nakshara, the distance between the sun and the earth gets reduced significantly resulting in days and nights getting hotter than the rest of summer months comparatively. During this period, maximum and minimum temperatures soar up.

According to the India Meteorological Department (IMD), the maximum temperatures could soar up to 47 degrees Celsius while minimum temperature could also soar up to 25-28 degrees Celsius in several parts of the country.

The IMD on Sunday issued a “red” warning for Delhi, Punjab, Haryana, Chandigarh and Rajasthan for the next two days. The IMD has also issued an orange warning for heatwave for east Uttar Pradesh. This is also for the first time this summer season that a red warning has been issued for heatwave.

According to Kuldeep Srivastava, the head of IMD’s Regional Meteorological Centre, this season, the temperatures did not rise the way it usually does in North and Central India because of significant rainfall activity during April that continued till mid-May. Srivastava said due to dry north-westerly winds and a trough between Chhattisgarh and Tamil Nadu, conditions are favourable for heatwave to severe heatwave.

“Heatwave conditions over some parts with severe heatwave over isolated pockets are very likely over Punjab, Haryana, Chandigarh, Delhi, Rajasthan, Uttar Pradesh, Madhya Pradesh, Vidarbha and Telnagana during the next five days,” the IMD said in its daily bulletin.

It added that heatwave conditions in isolated pockets over Chhattisgarh, Odisha, Gujarat, central Maharashtra and Vidarbha, coastal Andhra Pradesh, Yanam, Rayalseema and north interior Karnataka are also likely during the next 3-4 days.

A heatwave is declared when the maximum temperature is at least 40 degrees Celsius and the departure from normal temperature is 4.5 degrees Celsius to 6.4 degrees Celsius.  For the plains, a heatwave is declared when the actual maximum temperature is 45 degrees Celsius and severe heatwave when it is 47 degrees Celsius or above.

The IMD said relief is only expected after May 28 as a western disturbance is likely to bring some rainfall.  A western disturbance is a cyclonic storm that originates in the Mediterranean and travels across Central Asia. When it comes in contact with the Himalayas, it brings rains to the hills and plains.

The IMD issues colour-coded warnings depending on the intensity of any weather system in ascending order - green, yellow, orange and red. Srivastava said the red warning has been issued to caution people not to step out during 1 pm to 5 pm, when the intensity of the heat is the most.