“Why are they spending so much money on only a half a pair of pants?” he said. (Cue rimshot.)

Still, Hasidim have found subtle ways to beat the heat.

In Borough Park, women snatch up neckline-hugging shells that allow them to wear thin, long-sleeved and open-necked blouses from, say, Macy’s. Hasidic men seek a frock coat made of lighter-weight, drip-dry polyester, without a shape-holding canvas lining, and lightweight weaves in the fringed, four-cornered, woolen poncho known as tzitzit, a daily version of the prayer shawl that is worn over a white shirt. Also, men will go jacketless when working or driving, though any substantial stroll along a public sidewalk requires a suit jacket or frock coat, known in Yiddish as a rekel or in its longer and fancier Sabbath version as a bekishe.

Even the shtreimel, the tall, cylindrical, Russian sable hat that Hasidic men wear on the Sabbath to dignify the day, has been modified in recent years, with holes in the crown to provide a kind of ersatz air-conditioning. Those innovations may not seem to offer that much relief, but in Hasidic philosophy, it is more important to please God.

Beyond the law, the identifiable style of Hasidic clothing — even some waggish Hasidim call it a uniform — serves many purposes. It honors the way ancestors dressed in Europe starting in the 18th century, when the Hasidic movement was founded by sages who sought more joyous fervor in observance that could be expressed by the common folk. Many dress patterns, like the round, fur hats and knee-length frock coats, imitated the attire of the nobility. A style adopted by a movement’s grand rabbi filtered down through ardent acolytes.