Chazal say the two 21-day periods during the year, from Rosh Hashana to Hoshana Rabbah and from 17 Tammuz to the Tisha B’Av, correspond to the time it takes an egg to mature and an almond branch to blossom respectively. But from Shiva Asar B’Tammuz to Tisha B’Av is really 22 days!
Shiur provided courtesy of Torah Anytime