Easterlies rein in sun, but minimum temperature hits six-year high for May

The humidity in the past 24 hours oscillated between 62% and 37%, leading to a heat index of 55.4°C. The heat index can be defined as apparent temperature, which is what the temperature actually feels like.

Easterly winds from the Bay of Bengal continued to rein in the maximum temperature, with Delhi clocking 43.4°C on Wednesday, but the minimum temperature continued to rise, clocking 30.9°C, which was 4.2°C above normal and a six-year high recorded in the month of May, according to the India Meteorological Department (IMD).

Tourists shield themselves from the afternoon sun near Red Fort on Wednesday. (Sanchit Khanna/HT Photo)

The previous highest minimum temperature for May was recorded on May 13, 2018, when Delhi logged a minimum temperature of 31°C.

No heatwave was logged in the city for a second consecutive day, but IMD extended its heatwave alert till next Tuesday, issuing an orange alert for Thursday and a red alert from Friday to Sunday, forecasting the maximum temperature to touch 44°C by Thursday and 46°C by Saturday. The minimum is expected to hover around 32°C for the next few days.

The humidity in the past 24 hours oscillated between 62% and 37%, leading to a heat index of 55.4°C. The heat index can be defined as apparent temperature, which is what the temperature actually feels like. The heat index the day before was 45°C.

Kuldeep Srivastava, an IMD scientist, said, “Before the easterlies started blowing in, there was a lot of dry heat and the humidity stayed in the range of 20-25%. But the spike in humidity now has led to an uncomfortable feeling of extreme heat. The westerlies might start coming in from May 25.”

The maximum temperature of 43.4°C on the day, as recorded at the Safdarjung weather station — which is considered representative of Delhi weather — was three degrees above normal. The maximum temperature was 42.4°C on Tuesday and 44.1°C on Monday.

Other weather stations in the Capital also logged lower maximum temperatures on the day. Pusa, Raj Ghat and Palam stations recorded maximum temperatures of 42.6°C, 39.9°C and 41.6°C, respectively. The maximum at these stations a day before were 43.3°C, 40.3°C and 42.4°C, respectively.

Najafgarh recorded the highest maximum temperature on Wednesday, clocking 43.6°C, but it was also marginally lower than Tuesday’s reading of 43.9°C.

“The main reason that the maximum went down at multiple locations in the Capital is due to the easterlies coming from Bay of Bengal. The moisture content in the air has also gone up, as a result of which no heatwaves were observed,” an IMD official, requesting anonymity, said.

The official said, “However, the forecast for heatwave is still there. The severity of it will vary, depending on the moisture content. The upward trend in maximum and minimum is expected to continue for the next few days, till the western disturbances start coming in, which will have a lasting effect on the Capital’s weather.”

Meanwhile, Delhi’s air quality index (AQI) improved to the “moderate” category on the day, at 193, after nine consecutive days of “poor” AQI, according to the Central Pollution Control Board’s daily bulletin.

The Early Warning System (EWS) for Delhi, a forecasting model under the ministry of earth sciences, said: “The air quality is likely to be in ‘moderate’ category from May 23 to May 25. The outlook for subsequent six days is that the air quality is likely to be in poor to moderate category.”