Long ago, when the Rabbis shaped the Jewish calendar, they decided that seven times in a cycle of 19 years, we must insert an extra lunar moonth of Adar, to keep the Jewish calendar in tune with the solar year as well as the lunar moonth. 

Why was that important? They said it was to keep Passover in the spring. Otherwise,  it would circle through the solar year the way Ramadan does in the purely lunar Muslim calendar.

They also decided that whenever there was an extra Adar, the hilarious spring festival of Purim should always be in the  second Adar, to keep it  close to Passover.  (This year, Purim begins the evening of Wednesday, February 28.)

This raises two questions: Why did they think Passover must always come in Spring; and why did they think Purim should stay close to Pesach?

 I think they had politico-spiritual reasons for both decisions. Let's take up the second question first:

Both festivals are about the overthrow of a tyrant: Purim in early spring when the trees are putting on their fresh costumes, at a time when the Earth and human earthlings are redolent wth bawdy laighter — and Megillat Esther -- the Scroll of Esther --  is a doubling of a classic bawdy satirical joke  — the first Purimshpiel.

(Purimshpiels are plays, usually satirical and sometimes bawdy, that for centuries have been each year created and performed in and by Jewish communities.  Some modern scholars  suggest that the Scroll of Esther was by no means a history but a satire and parody on tyrannical rulers. They suggest that the hilarious spring festival of Purim led to the creation of the Scroll of Esther as the first and still the greatest of all Purimshpiels -- not that the story of Esther calls forth a new holy day.)

(In this painting by Ari Gradus, we see the first comic reversal in the story: the anti-Semitic genocidal Prime Minister Haman is forced to honor the Jewish leader Mordechai. For Gradus' work, see <http://rogallery.com/gradus_ari/gradus_hm.htm>)

In that sense, Purim is an experiment in overcoming tyrants through laughter — as Saturday Night Live and much of our late-night TV comedy these days is aimed at our own pompous, cruel, and vicious rulers.

That is the nusach, the melody, of early spring. Then comes the nusach of “serious” spring. With Passover, YyyyHhhhWwwwHhhh, the Breath of Life, the Wind of Change,  becomes a Hurricane of Transformation. Is the sequence a reminder that we should began overthrowing our tyrants with laughter and if that is insufficient, we need to turn to more “serious" measures of Resistance?

Just to clarify why I said the Megillah is a double joke:  

The genocidal "white-nationalist" Prime Minister Haman starts the anti-Jewish action that ends up destroying him. (Even the same gallows he had intended for the Jewish leader Mordechai ends up hanging him). A bloody joke, of the classic "hoist on his own petard,” "trip on your own banana peel" form.

AND — there is in the Megillah another joke of the same form, less bloody: King Ahasuerus starts the action going with his put-down of Queen Vashti — women must not disobey men. And the result of his own anti-feminist tyranny is that he abjectly obeys what a woman -- the new Queen Esther -- tells him to do.

(Look carefully at the King. Here we see what Ahasuerus looks lke in our generation, with Haman lurking just behind.)

Anti-Semitism & anti-feminism go hand in hand (as they do in our present White House). Indeed, there is ancient midrash that says the courtier Memucan, who advised the King to get rid of Queen Vashti, was Haman in disguise! Ahasuerus may seem to be a pompous, empty-headed, self-obsessed fool -- but remember, he affirms Haman's tyrannical plot.