This seems appropriate for the season: Sir Thomas Malory's digression on "how true love is likened to summer" in Book XVIII of Le Morte d'Arthur (as edited by Caxton).
'And thus it passed on from Candlemas until after Easter, that the month of May was come, when every lusty heart beginneth to blossom, and to bring forth fruit; for like as herbs and trees bring forth fruit and flourish in May, in like wise every lusty heart that is in any manner a lover, springeth and flourisheth in lusty deeds. For it giveth unto all lovers courage, that lusty month of May, in something to constrain him to some manner of thing more in that month than in any other month, for divers causes.
For then all herbs and trees renew a man and woman, and likewise lovers call again to their mind old gentleness and old service, and many kind deeds that were forgotten by negligence. For like as winter rasure doth alway arase and deface green summer, so fareth it by unstable love in man and woman. For in many persons there is no stability; for we may see all day, for a little blast of winter's rasure, anon we shall deface and lay apart true love for little or nought, that cost much thing; this is no wisdom nor stability, but it is feebleness of nature and great disworship, whosomever useth this.
Therefore, like as May month flowereth and flourisheth in many gardens, so in like wise let every man of worship flourish his heart in this world, first unto God, and next unto the joy of them that he promised his faith unto; for there was never worshipful man or worshipful woman, but they loved one better than another; and worship in arms may never be foiled, but first reserve the honour to God, and secondly the quarrel must come of thy lady: and such love I call virtuous love.
But nowadays men can not love seven night but they must have all their desires: that love may not endure by reason; for where they be soon accorded and hasty heat, soon it cooleth. Right so fareth love nowadays, soon hot soon cold: this is no stability. But the old love was not so; men and women could love together seven years, and no licours lusts were between them, and then was love, truth, and faithfulness: and lo, in like wise was used love in King Arthur's days.
Wherefore I liken love nowadays unto summer and winter; for like as the one is hot and the other cold, so fareth love nowadays; therefore all ye that be lovers call unto your remembrance the month of May, like as did Queen Guenever, for whom I make here a little mention, that while she lived she was a true lover, and therefore she had a good end.'