On Karva Chauth married women in northern India fast from before dawn, and the fast ends only when the Moon has actually been sighted — through a sieve, then looking at the husband through the same sieve.

It falls four days after the full moon of Kartika, so the moon rises late in the evening and the wait is long. A cloudy night genuinely extends the fast. Almost nothing else in modern life makes a person stand outside scanning for a moonrise, and this does it for millions of people on one evening a year.