Why Delhi Faced Extreme Heat on Republic Day

Delhi Registers Warmest Republic Day in Eight Years, Air Quality Declines
It has been the warmest Republic Day in eight years for the capital. The temperature touched 23.7 degrees Celsius during the day with the India Meteorological Department said, two degrees more than normal. The city was warmer than even the long period average (LPA) for a maximum of 22.1 degrees Celsius recorded on January 26, something that last occurred in 2017 when 26.1 degrees Celsius was noted on the same day.

IMD said that the unusual rise in temperature was because of clear skies and dry northwesterly winds that permitted sunlight to enter unbroken and heat to remain there all day long. However, it had ensured clear visibility for the Republic Day Parade, unlike last week, which had seen foggy conditions, which had caused various kinds of disturbances for the morning.

Weather Shifting Was Noticed
The lowest level on January 26 was recorded as 7.2 degrees Celsius in Delhi. This was well below the average for that day, which normally had recorded an average temperature of 8 degrees Celsius. It was even lower than for the past few days when temperatures had reached 8.6 degrees Celsius on January 25 and a high of 9.8 degrees Celsius on January 24.

The temperature of the city on Republic Day has been mostly variable over the years. Delhi had a maximum of 20.6 degrees Celsius in 2024, 17.3 degrees Celsius in 2023, and 16.4 degrees Celsius in 2022.

Western Disturbances Impact
According to the IMD, there had been a recent western disturbance that brought in rain and snow for northwest India but the bright sunshine at the day wasn't enough to affect the maximum temperature of Delhi.

But the western disturbance has an offshoot on January 28. That is likely to modify wind direction and wind speed with the possibility of higher clouding. That should cause the nights to warm and cause minimum temperature to be elevated.
Minimum temperature for the weekend according to IMD forecast, can be at 9-11 degrees Celsius with a maximum hovers around 24-26 degrees Celsius.

Eroding Air Quality
It remained in the "moderate" category on 25 January but deteriorated to a "poor" category on January 26 with an AQI of 216 based on the Air Quality Early Warning System. The AQI was already at 225 by 8:30 a.m. on January 26.

AQEWS has predicted that from January 27 and 28, the air quality will be in the "poor" category but may deteriorate to "very poor" from January 29 onwards. This deterioration might continue for the next six days of low wind speed and high concentration of pollution.

Why Is Delhi Warm?
Above normal maxima are being caused in Delhi due to clear skies and dry winds coming from northwest that enable sufficient scope for maximum solar heating during the daytime itself while letting off heat rapidly through radiations during the night resulting in cooler minima.

The next western disturbance could intervene over this event by bringing clouding action which is meant to be retentive of heat overnight thus raising minimums ahead.
The weather in Delhi during the next week would be influenced by the western disturbance that is going to hit the region. Moreover, the air quality would deteriorate further as the AQI is expected to enter the "very poor" category.
The instances of increasing temperatures and degrading air quality tell us that challenges climate variability and urban pollution pile up every day.

Source: India Meteorological Department, PTI