Number Theory: Why November went from being abnormally hot to abnormally cold

The average maximum temperature for India for the month (up to November 28) was 28.90°C, only 0.14°C warmer than the 1981-2010 average for this period.

The India Meteorological Department (IMD) treats December as the beginning of the winter season. In large parts of north India, the winter chill is usually expected to set in much earlier and this is what was missing for a large part of November. Was November warmer than usual? Not the month as a whole, but definitely in the first half, an HT analysis of IMD’s gridded dataset shows.

A man sits next to a bonfire on a cold winter morning in Noida on November 21. (Photo by Sunil Ghosh / Hindustan Times)