The second day of this year's severe cold is New Year's Eve. Why is 15 days missing?

Because this year's lunar calendar is a normal year.

The calculation method of the lunar calendar in China is generally determined by the 24 solar terms, but the days of 12 lunar month are not as old as the 24 solar terms. For example, we often see that there are only 23 solar terms in the Gregorian calendar in a certain year, or there is an extra solar term in a certain year, which is how it came about.

But if it is counted as 13 lunar month, it will exceed. Therefore, the state adopts the method of timely adding leap month to mediate, and basically every two or three years, a leap month will be added to adjust the difference.

In other words, the 10 day of the lunar calendar in 2022 will be added in the next leap year.