The traditional dating is somewhat unusual in that it varies from year to year, although the same formula is applied. Easter is determined by the lunar calendar, which is based on the phases of the moon. Easter has a “general window” based on a combination of the movements of the sun and the moon. The anchor celestial event is the spring equinox (if your perspective is from the northern hemisphere) or the autumn equinox (if your perspective is from the southern hemisphere.)
The spring equinox is when the sun crosses the celestial equator–the imaginary line in the sky above the Earth’s equator, as the sun heads from south to north. So, Easter in the southern hemisphere is always observed in the autumn season as the prelude to winter. In the northern hemisphere it is the reverse: Easter heralds the onset of spring and the coming summer.
Once the spring (or autumn) equinox has occurred, Easter falls on the first Sunday after the first full moon after the Spring Equinox around March 20. Thus, it will always fall sometime between March 22 and April 25. This year it falls on the 30th May through April 1st.
The precise date year on year is of no importance or significance. Nor is the particular calculation formula. If it were to be regarded as significant then probably it would be to reference historical Christian tradition and continuity–and little more.
What then shall we say to these things? If God is for us, who can be against us? He who did not spare his own Son but gave him up for us all, how will he not also with him graciously give us all things? Who shall bring any charge against God’s elect? It is God who justifies. Who is to condemn? Christ Jesus is the one who died—more than that, who was raised—who is at the right hand of God, who indeed is interceding for us. [Romans 8: 31-34]
For Christ also suffered once for sins, the righteous for the unrighteous, that he might bring us to God, being put to death in the flesh but made alive in the spirit . . . who has gone into heaven and is at the right hand of God, with angels, authorities, and powers having been subjected to him. [I Peter 3: 18-22]
Upon these things the entire creation turns. These things are the adamant the indestructible and certain realities that every living being will, in the end, be brought to acknowledge.
It is appropriate at Easter to stand back and take the broader, higher view, whilst we take our refuge in Him:
Why do the nations rage and the peoples plot in vain? The kings of the earth set themselves, and the rulers take counsel together, against the Lord and against his Anointed, saying, “Let us burst their bonds apart and cast away their cords from us.”
He who sits in the heavens laughs; the Lord holds them in derision. Then he will speak to them in his wrath, and terrify them in his fury, saying, “As for me, I have set my King on Zion, my holy hill.”
I will tell of the decree: The Lord said to me, “You are my Son; today I have begotten you. Ask of me, and I will make the nations your heritage, and the ends of the earth your possession. You shall break them with a rod of iron and dash them in pieces like a potter’s vessel.”
Now therefore, O kings, be wise; be warned, O rulers of the earth. Serve the Lord with fear, and rejoice with trembling. Kiss the Son, lest he be angry, and you perish in the way, for his wrath is quickly kindled.
Blessed are all who take refuge in him. [Psalm 2]