The sky has been clear in Delhi for a week. Over the next seven days, that may not always be the case. The seven-day forecast released on February 21 by the Regional Meteorological Center of the Indian Meteorological Department in Delhi indicates that the sky will be partly cloudy in Delhi from February 22 to February 24, with strong winds on the first two of these three days. . However, the maximum temperature in the city-state will fluctuate between 26 and 29 degrees Celsius. This is about 2 to 4 degrees higher than the average temperature of these days in the period 1981-2010, considered normal. How warmer than normal have February days been so far? Here are four tables that explain it.
February was closer to normal than January, but did not exceed it on average
According to the weather bureau’s gridded temperature dataset, which covers an area slightly larger than the boundaries of Delh, this January was the coldest since 1951 in terms of maximum temperature. The average high temperature for the month was 17.35 degrees, 3.37 degrees or 16% below normal. This average during the first three weeks of February (until February 20), considered the last month of winter in northern India, was much milder and only 2.8% lower than the normal. February 27 is still the coldest since 1951. Certainly minimum temperatures were above normal in January (24.9% above normal) and February (8.6% above normal). above normal), making this year the second and 23rd warmest this year. metric for those months, respectively. However, even on this point, February is closer to normal than January.
Graph 1: Average maximum and minimum temperature in Delhi (degrees Celsius)
Why is February even colder than normal on average?
The reason is what happened the first week of February. This year was respectively the coldest, the second and the third coldest year since 1951 on February 3, 4 and 5. In absolute terms, the first five days of February had maximum temperatures of 3.2 degrees, 0.5 degrees, 7.7 degrees, 5.4 degrees and 4.8 degrees below normal. Despite clearer skies compared to January, this temperature was above normal in February for only nine days until February 20, including seven days from February 13 to 19. amount by which it was below normal in the first week of February. During the nine days of above normal temperatures, the most deviated maximum temperature is 2.5 degrees. This made it harder for the average temperature in February 2022 to catch up to normal.
Graph 2: Daily maximum temperature in Delhi (degrees Celsius)
Rainfall interrupted any steady rise in temperature
The maximum temperature has been above normal in Delhi for just 12 days so far this year, including seven in the past week alone. Why didn’t this happen before this February period? The reason is that there were two rainy spells before February 15 not only in Delhi but also in the northwestern states of Punjab, Haryana, Rajasthan, Himachal Pradesh and Uttarakhand, and neighboring Uttar Pradesh. These two episodes took place between February 3 and 5 and between February 9 and 10. There was also precipitation in some of these states from February 16, but it was not even 5% of the precipitation of the first half of February in any of these states. the states.
Graph 3: Precipitation in February (mm)
Low temperatures are not only the result of precipitation
Rainfall is not the only reason why temperatures have been low in Delhi. Windy conditions when it was not raining could have kept temperatures low. Although not an infallible measure, the air quality in Delhi is an indication. Delhi’s air quality index was the best or second best since 2018 for 10 out of 20 days in February. Only three of those days came last week, when warmer temperatures could also have contributed to good air quality. Eight of the days occurred when it did not rain in Delhi and three days when it did not rain in neighboring states either.
Figure 4: AQI in Delhi