New Delhi: Delhi witnessed an unusually warm night, with the minimum temperature settling at 28.4 degrees Celsius, 4.6 degrees above normal, at base station Safdarjung. It was the warmest April night in nine years when the temperature touched 29 degrees Celsius on April 22, 2017. On April 28, 2018, too, the city recorded the minimum temperature at 28.4 degrees Celsius.While a heatwave is declared based on high daytime temperatures, India Meteorological Department (IMD) considers a ‘warm night’ when the maximum temperature exceeds 40 degrees Celsius and the minimum remains more than 4.5 degrees above normal. Although both Safdarjung and Aya Nagar (29.1 degrees Celsius) met the criteria, IMD said a warm night would be officially declared if multiple stations met the threshold on Wednesday as well.The minimum temperature was 25 degrees Celsius on Monday. It is likely to remain between 26 and 28 degrees Celsius on Wednesday and 25-27 degrees Celsius on Thursday.The overcast skies caused the mercury to dip below the 40-degree mark after a gap of six days. The maximum temperature dipped to 39.2 degrees Celsius, which is near normal for this time of the year. It was 42.3 degrees Celsius a day earlier. Between 2.30pm and 5.30pm, Lodhi Road and Palam saw ‘trace’ rainfall while gusty winds blew briefly in parts of the city.IMD has issued a yellow alert for Wednesday for very light to light rain accompanied by thunderstorms, lightning and gusty winds of up to 50kmph. Similar weather is expected on Thursday, but the Met department has not issued any colour-coded warning. “The maximum temperatures fell by three to five degrees across Delhi on Tuesday. It is likely to remain below 40 degrees Celsius till at least Thursday,” said an official.The month is expected to end on a rainy note. As clear skies are likely to return from May 1, the mercury is expected to start gradually rising. It may increase to 40-42 degrees Celsius by May 2. “However, there is possibility of very light rain and thunderstorms on May 3 and 4,” said the official.The city reeled under three days of heatwave conditions between Thursday and Saturday. Though isolated heatwave was recorded in parts of the city on Thursday and Friday, a citywide heatwave was declared on Saturday when the mercury touched 42.8 degrees Celsius, making it the hottest April day in four years.This season, the second half of March was relatively cooler due to back-to-back western disturbances causing light rain and overcast skies. This continued in the first week of April when rain activities kept the day temperature mostly below normal.Meanwhile, the city’s air quality worsened to poor with an AQI of 239 against 197 (moderate) on Monday. The air quality is predicted to be moderate from Wednesday to Friday, according to Air Quality Early Warning System for Delhi.
