Why does the Queen have two different birthdays?

Yes, Queen Elizabeth II was born on April 21st, 1926, meaning she'll be turning 92 on Saturday. But her "official" birthday is actually June 9th. So, why does the queen have two birthdays?

The tradition of "official" royal birthdays started in 1748 by King George, who didn't want his birthday celebration to be ruined by cold weather, rain, or even snow. So, he decided to celebrate an "official" birthday each year when the weather was better in May or June. Since then, every British monarch has had this option.

But this year, the queen will be celebrating on her actual birthday, April 21st, with a party including performances by Shaggy, Sting, Kylie Minogue, Craig David, Shawn Mendes, and Tom Jones.