I spring train in the winter
Round early December

from Jay Z – Breathe Easy (Lyrical Exercise) Lyrics on Rap Genius

Meaning

Jay is ready for rap battles way in advance of his matches since he has so many lines packed away in his brain. I wonder if he takes a day off for his birthday

Also a reference to how he used to try to release his albums around the fourth quarter of the year, so by December he’d start preparing for another album

Reasonable DoubtJune (odd one out)
In My Lifetime, Vol. 1November
Vol. 2… Hard Knock LifeSeptember
Vol. 3… Life and Times of S. CarterDecember
The Dynasty: Roc La FamiliaOctober
The BlueprintSeptember

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