Delhi recorded the second “warm night” this season, as the minimum temperature remained over 30°C amid slow-moving dust from Rajasthan in the early hours of Monday, even as a yellow alert remained in place for continuing intense heat in the region.A “warm night” occurs when the maximum temperature is over 40°C in the plains, and the minimum temperature is 4.5°C or more above normal. (HT PHOTO)A “warm night” occurs when the maximum temperature is over 40°C in the plains, and the minimum temperature is 4.5°C or more above normal.Safdarjung, Delhi’s base weather station, logged a minimum temperature of 32.4°C, six degrees above normal, making it the warmest night for Delhi in May in 14 years. The last time it was higher was on May 27, 2012, at 34.2°C, India Meteorological Department (IMD) data showed. This eclipses the 31.9°C Delhi recorded on May 21, the season’s first “warm night”.Delhi’s air quality was in the lower end of the “poor” category. An air quality Index (AQI) of 206 was recorded at 9am, compared to 205 at 4pm on Sunday.There are chances of isolated heatwave conditions. Scattered light rain and gusty winds of up to 60 km/hr may occur between noon and evening, and the maximum temperature may still hover between 43-45°C. On Wednesday, Delhi recorded a minimum temperature of 28.7°C, which was two degrees above normal.A “heatwave” is when the maximum temperature is over 40°C, with the departure being 4.5°C or more above normal. It is also a heatwave if the maximum temperature is over 45°C in the plains. “Severe heatwave” is when the maximum is over 40°C, and the departure is 6.5°C or more above normal.An IMD official said “warm night” conditions were recorded at Safdarjung, Ayanagar, and Lodhi Road as slow-moving dust led to a haze-like situation in Delhi and other parts of northwest India on Sunday night. The IMD issued a yellow alert for possible dust-raising winds in Delhi at 6pm, but its impact was felt around 9:30pm. “By 9 and 9:30pm, dust was being detected in Delhi and adjoining regions. There is a haze at Palam, Jaipur, Lucknow, and Amritsar,” another IMD official said.There are chances of rain in Delhi from May 28-30, as a fresh western disturbance starts to impact northwest India from May 28.