How many days does a severe cold always last?

Great cold *** 15 days. The traditional 254 solar terms take five days as the waiting period, 15 days as a solar term, and the severe cold solar term is one of the traditional 24 solar terms, and the time is also 15 days. In cold festivals, the temperature is low, it will be very cold, and it will often snow. There is a folk proverb called "auspicious snow indicates a good year".