Chillai Kalan or Chilla-i-Kalan (Kashmiri pronunciation: [t͡ʃilaj kalaːn] , Translation : forty days of intense cold)[1] is the local name given to 40 day period of harsh winter in Kashmir.[2] It is the coldest part of winter, starting from 21 December to January 29 every year. Chillai-Kalan is followed by 20-day long Chillai Khurd (Kashmiri pronunciation: [t͡ʃilaj kʰɔrɨd] , Translation : small cold) that occurs between January 30 and February 18 and a 10-days long Chillai Bachha (Kashmiri pronunciation: [t͡ʃilɨ bat͡ʃi] , Translation : baby cold) which is from February 19 to February 28.[3]
During this 40 day period in Kashmir, nights are chilly and day temperatures thrive in single digits. During Chillai-Kalan, the weather in valley of Kashmir continues to remain cold with minimum temperatures hovering below the freezing point. The snow that falls during this time period freezes and lasts longer. It is this snow that adds to the glaciers of the Valley and replenishes the perennial reservoirs that feed the rivers, streams and lakes in Kashmir during the months of summer. Any snowfall after the chillai kalan does not last long.
Chillai Kalan affects the daily life of Kashmiris. Use of Pheran (Kashmiri dress) and a traditional firing pot called Kanger increases.[5] Due to subzero temperatures, tap water pipelines freeze partially during this period and the Dal Lake also freezes.[6][7] Tourist resorts like Sonamarg and Gulmarg receive heavy snow.[8]