For three consecutive Septembers, Louisville singer/songwriter Joan Shelley has arrived with new music perfectly suited to the transition between summer and fall. Her latest single, “Cost of the Cold,” was inspired by “a particular waterfall, dog, and recent season in Kentucky,” and it’s one of Shelley’s finest compositions yet, a reflection on the changing world and the intimate connections that hold everything together. Of course, one of the crucial intimacies in Shelley’s own music is the interplay between her and guitarist Nathan Salsburg, whose stately fingerpicking has accompanied each of her recent records. On this single, the pair is also joined by James Elkington, a musician with whom Salsburg has a long history of collaborating.

A natural progression from the early morning musings that made Over and Even one of last year’s most distinctive folk albums, “Cost of the Cold” finds the three players locked into an earthy, clear-eyed groove. A slow pulse guides the song before it opens into a gorgeous refrain of acoustic guitar, quiet keys, and background vocals. “Fire warms and fire burns,” Shelley sings, “And now I have learned the cost of the cold.” They’re the words of a songwriter who has seen it all from both sides now, delivered with patience and certainty. At this point, it’s hard to imagine getting through autumn without her.