Very much on the expected lines, the minimum temperature has risen over Delhi and gone above the average. Even, the day temperature also is above normal by about 2°C. The minimum temperature today morning, as recorded at base station Safdarjung was 20.3°C. The minimum was clocking under 20°C for the last five days in a row, with the lowest of 17.4°C on 15th October. The mercury levels are unlikely to plunge over the next one week. However, a marginal change of about +/- 1°-2°C is quite possible.
Pockets of Delhi itself have a large differential with respect to mercury levels. Today morning, the Ridge area recorded a low of 16.4°C and Pitampura registered a minimum of 23.1°C. The exposure and the surroundings drive these temperatures and a large swing is noticed on many such occasions. This will be a routine feature, throughout the season.
Invariably, the national capital records its lowest temperature of October at the fag end of the month. It stands to a logic, as well. Similar conditions are expected this season also. The lowest temperature of 20°C or above may not be sustained for long, but any typical drop is also unlikely.
All these lowest temperatures were recorded on or after the 25th of October. The lowest of all at 12.5°C in Oct 2020 was recorded on 29th Oct. Last year, the lowest of 14.3°C was registered on 28th October. More often than not, the minimum temperatures remain below 20°C during the second half of the month and frequently drop to under 15°C in the last week of the month.
The temperature drop is normally associated with moderate northwesterly winds, dry and cold, blowing down the slopes of mountains and sweeping plains of North India, including Delhi. Such a scenario is unlikely for the next one week. There is no snowfall expected over the mountains, not even in the higher reaches. Rather the winds are going to be light and variable, under the influence of an anticyclonic pattern over parts of Southwest Uttar Pradesh, North Madhya Pradesh and the neighbouring Rajasthan region, in the lower levels of the atmosphere. This pattern is likely to persist till 22nd October. There are precursors to a likely western disturbance arriving on 23rd Oct and reversing the winds and weather conditions over the plains, including Delhi. The approach of this system will further arrest any significant drop in mercury levels. Though it is premature to comment, but the weather system will hang around till 26th October. The minimum temperature is expected to nosedive in the last week of October, possibly commencing on 27th October. Typical winter chill can be expected, following the same track, as in the past, during the concluding days of October.