After two days of a persistent heat wave, the National Capital and surrounding regions on Thursday saw "very slight" respite, as average maximum temperature stood at 43 degrees Celsius, three notches above the season's average. The heat wave will return from Friday onwards and will continue till at least Monday, affecting Delhi along with north, central and east India, Met scientists told IANS. The next respite is only likely towards the end of May or first week of June, weather analysts said. Friday's average maximum temperature is likely to hover around 44 to 45 degrees, while Palam is expected to be hotter. On Thursday, Palam at 44.1 degrees, four notches above the season's average, was the warmest place in Delhi, causing heat waves with inductive effect on the rest of the region. Gurugram and Faridabad sizzled at 43 degrees. Thursday's minimum temperature was recorded at 26.5 degrees, the season's average. A duststorm and thunderstorm, which was supposed to sooth the evening in Delhi, was also averted as the cyclonic circulation over the central Uttar Pradesh was confined to northern Madhya Pradesh and could not make it to the National Capital Region. "There were some easterly winds in Delhi, which are moist due to which the heat waves were averted, but mercury will gradually rise from Friday onwards and last till the month-end or at least till May 28," Kuldeep Srivastava, scientist at India Meteorological Department (IMD), told IANS. According to IMD, the heat waves are caused when either the temperature is or above 45 degrees, or if mercury crosses 40 degrees but is five degrees higher than the season's average. "A cyclonic circulation along with western disturbance might have effects over Jammu and Kashmir towards May 29, so temperatures may fall in Delhi but warming will still be there," Srivastava added. However, according to private weather forecasting agency Skymet, respite is only likely at the end of May. "There had been variation in the winds. light rains which would bring the much-needed respite are only likely around May 31 and not before that as was being expected earlier," Mahesh Palawat, Skymet Director, told IANS. The humidity on Thursday oscillated between 27 to 38 per cent. Even as heat waves were averted by few notches of mercury in Delhi and surrounding areas, the orange warning - "severe heat alert for the day" - continues for Delhi till May 28, including Rajasthan, Haryana, Punjab, western and eastern Madhya Pradesh, northern Gujarat and Kutch, western Uttar Pradesh, Uttarakhand, Himachal Pradesh sand Vidharba in Maharashtra. Wednesday's maximum temperature was recorded at 43 degrees, three notches above the season's average while the minimum temperature was 26.7 degrees, the season's average.