With the onset of summer, an abnormal high temperature and heat wave condition is prevailing in some parts of the country, the weather office said on Tuesday.

In the month of March, the normal temperatures in central India are around 32-34 degree centigrade and in northwest India and the northern plains is 30 degree centigrade.

But most parts of north and northwest India, including Maharashtra and Madhya Pradesh, are experiencing temperatures 6-7 degree centigrade above normal while down south it is 3-4 degree centigrade above normal.

Deputy Director General S K Subramaniam of the Indian Meteorological Department (IMD), said: "Temperatures all over the country are abnormal these days. This phenomenon does occur in March. It is nothing new."

In West Bengal and Orrisa, temperatures are hovering around 37-38 degree, in Bihar 33-35 degree, in southern Rajasthan and western Madhya Pradesh 41-43 degree and in central Madhya Pradesh, northern Maharashtra and Andhra Pradesh 40 degree centigrade.

In the southern part of India, temperatures are between 36 and 39 degree. In the northeast, it is around 35-36 degree centigrade.

Temperatures in south India these days is considered 3-4 degree above normal, in Andhra Pradesh 4-5 degree above normal, in Bihar 2-3 degree above normal, in Orrisa 3-4 degree above normal and in Guwahati 4-5 degree above normal.

The 'heat wave condition' extends to parts of Gujarat, southern Rajasthan, parts of Madhya Pradesh, Vidarbha and Marathwada.

A heat wave condition is considered to exist when the temperature is either above 40 degree centigrade or 5-6 degree above normal, said Subramaniam.

Subramaniam explains the abnormal rise in temperatures. "As summer approaches, temperatures are bound to rise. But it has a counter in the form of the Western Disturbance, which moderates the temperature in the country. Its absence this year has meant that temperatures continue to rise abnormally," he said.

Western Disturbance is a phenomenon in which cold air from Afghanistan and Pakistan moves over India and covers large parts of the country, preventing temperatures from rising.

"The rise in temperatures is due to radiation heat and the warm air stagnating over India. With no cold air coming in, there is continued and persistent heating," Subramaniam said.

R D Singh, chief of the weather department's northwest region, says the temperatures may return to normal by the end of March or early April. "However, this is not certain," he added.

Generally, most parts of north India experience light drizzles in March, which also marginally brings down the temperature.

"The increase has been only in the maximum temperatures. The minimum is almost normal," R D Singh pointed out.

In Delhi this year, the minimum temperature was 12 degree centigrade and maximum 26 degree on March 1. On March 16, the minimum was 17 degree while the maximum went up to 33 degree centigrade. So far, the maximum temperature recorded in Delhi in the month of March has been 40.6 degree centigrade on March 31, 1945.