Vaughn Ryan Midder as Jeron and Jeremy Keith Hunter as Devaun in “When January Feels Like Summer.” (Stan Barouh/ )

Jeremy Keith Hunter has secured himself a “carpe diem” role, and believe me, he is seizing the comic day. As Devaun, the risibly unschooled but surprisingly compassionate ladies’ man of Cori Thomas’s “When January Feels Like Summer,” Hunter is getting the kind of muscle-stretching showcase for which some actors wait half a lifetime.

His is not the only admirable performance in Thomas’s sweet, if at times cloyingly overwritten, Harlem-set comedy, receiving its regional premiere as the final entry of Mosaic Theater Company’s freshman season. The four actors working with him under director Serge Seiden’s expert guidance — Vaughn Ryan Midder, Lynette Rathnam, Shravan Amin and Jason B. McIntosh — inhabit their more reserved roles just as compellingly. And in the case of Amin, playing a South Asian immigrant making a gender transition from Ishan to Indira, the actor’s projection of quiet, courageous resolve offers a touching counterpoint to Hunter’s bravado.

In “When January Feels Like Summer,” running at the Atlas Performing Arts Center on H Street NE, Thomas explores with gentle humor the development of a pair of romances — one of them especially unlikely — across an ethnic chasm. The Harlem deli run by Ishan’s sister, Rathnam’s Nirmala, is a breeding ground for love as lonely garbageman Joe (McIntosh) fixes his sights on equally lovelorn Nirmala, while oblivious Devaun takes a liking to the deeply flattered, in-transition Indira.

The potential for patronizing mechanics hovers over this endeavor, with regard both to Ishan/Indira’s fervent embrace of womanhood, and the outrageous homeboy antics of Devaun, who uses words like “particularily” and doesn’t quite grasp the cause-and-effect aspects of global warming, as explained to him by his best friend, Midder’s Jeron. If at first Devaun is portrayed as loudly, clownishly confused — he becomes convinced that Antarctic penguins are dying directly as the result of people not correctly separating their recyclables — the playwright eventually reveals a redeeming generosity of spirit in the character.

Midder and Hunter’s natural magnetism, combined with their wry grasps of the world Jeron and Devaun come from, ultimately temper any unease an audience may develop over aspects of the characters that border on caricature. A linchpin of the plot is a naively hatched plan by Jeron and Devaun to put up warning posters in the neighborhood about an older gentleman who propositioned Devaun in another deli. The scheme reeks of homophobic overreaction, but in one of the play’s more ironic (and contrived) twists, their campaign proves oddly beneficial, and as a result, their fortunes take a turn for the better.

Shravan Amin as Ishan/ Indira and Lynette Rathnam as Nirmala in “When January Feels Like Summer.” (Stan Barouh)

Thomas’s comedy is all about unintended consequences: The title refers to the alteration in New York weather patterns brought on by human-instigated climate change. In its frequent depictions onstage of radical shifts in temperature and atmospheric conditions, the play underlines the concept a bit too transparently. It’s not only Devaun, though, who shows a capacity for growth and change: Shamed, inhibited Nirmala, consumed with guilt over her anger toward the husband who lies comatose in a hospital, moves with the encouragement of forbearing Joe toward a belief that she is worthy of love.

As he does with the other actors, Seiden ably steers Rathnam and McIntosh to the kind of tender resolution that appeals to the cheesy sentimentalist in all of us. The play is performed with virtually no visual embroidery: Debra Booth’s spartan set consists of simply a few seats in a subway car, a deli cashier’s counter, and a wooden table and chairs. The more important theatrical feature here is the commitment Mosaic Theater makes to a quintet of actors of color who get the chance to play full-bodied characters with abundant heart — and act their hearts out in the process.

When January Feels Like Summer by Cori Thomas. Directed by Serge Seiden. Set, Debra Booth; lighting, Max Doolittle; costumes, Robert Croghan; sound, David Lamont Wilson. About 2 hours 15 minutes. Tickets, $40-$60. Visit mosaictheater.org or call 202-399-7993 ext. 2.