Nights can drop to 2–5°C, while daytime hovers around a pleasant 20°C. Hotels may not have great heating — Delhi was not built for cold, and many buildings respond to winter the way a beach house responds to snow: with confusion and inadequacy.
Pack layers. The one great advantage of winter is that you can walk greater distances with relative ease — essential when exploring Old Delhi’s lanes or the broad avenues around Connaught Place.
Just keep that N95 mask on, and you’ll be fine.