TAMPA, Fla. (WFLA) — Easter is always on Sunday, which means the date for the holiday will vary from year to year—just like Memorial Day or Labor Day—and can sometimes fall on different months.

So how is the date for Easter determined?

The spring equinox and a full moon play an important role. Easter is always the Sunday after the first full moon that is after the spring equinox.

This year, the spring equinox was on March 20. The first full moon after that occurred on April 16. The first Sunday after that is on April 17, which is why Easter falls on that date this year.

The earliest Easter in the 21st century is on March 23, and the latest it will occur is on April 25. That’s a 34-day difference.

The full moon that decides Easter is known as the Paschal moon, but this year, the full April “Pink moon” decided the date. The pink moon was named after the pink wildflowers that bloom in early spring.

It is technically full at 12:55 pm April 16, so here in Florida we won’t see it at it’s fullest moment but it will appear full both Friday night and Saturday night.

Sunrise is at 7:02 am Sunday morning. Civil twilight will begin at 6:38 am.

It will be a warm and muggy start to the day with a few clouds in the sky but it should be dry. A light breeze will pick up in the morning and temps will warm into the upper 80s Sunday afternoon. A few scattered showers will be possible with a 20% rain chance.