Nepal, Feb. 10 -- The atmosphere engulfed by a thick fog and grounds frosty, Kathmandu Valley would have already been deep into winter by mid-Mangsir. Sitting for final exams, Sagar Neupane's hands turned stiff with freezing cold and his heart stirred a little in the fear that he might fail. But there was something that warmed his core.

"More than the fear of failing the exams, my heart would be filled with the happy anticipation of minpachas right around the corner," said the 60-year-old from Chuchhepati.

Minpachas (min means fish, pachas is fifty in Nepali) or the fifty days from mid-Mangsir to mid-Magh were so cold that even fishes deep under the waters hid below the rocks to keep warm. And schools closed.

As biting cold gripped the...