In addition to holidays like Christmas and Hanukkah, Maine residents celebrate the invention of earmuffs each December. Their appreciation for the winter wardrobe staple runs deeper than most, as Chester Greenwood—who is credited with inventing the modern-day earmuff at age 15—hailed from Farmington, Maine, according to the Associated Press.

In 1977, Maine's legislature designated December 21 (typically the first day of winter) as Chester Greenwood Day. The annual state holiday celebrates Greenwood and his snug ear coverings, which he first created in 1873.

As The Washington Post reports, Greenwood loved to ice skate, but hated the frostbite that plagued his sensitive ears. The teen was reportedly allergic to wool caps with earflaps, so he asked his grandma to sew either little flannel or fur pads onto the ends of a bent wire ring. Greenwood wore the contraption around his head, and it wasn’t long before his friends (who initially made fun of the headgear) had also adopted the look.

Greenwood tweaked his cold-weather accessory over the years, replacing the wire with bands and adding hinges to the ear pads, among other changes. In his mid-twenties, the inventor launched his own factory near Farmington, employing 11 workers who produced as many as 50,000 pairs of earmuffs in a single year. By the time Greenwood died in 1937, the number had skyrocketed to 400,000.

Some say that Greenwood technically didn’t pioneer the concept of earmuffs. He simply perfected the design by adding the earflap hinges that provide extra pressure, patent agents say. Still, the Farmington native would go on to invent nearly 100 other devices, five of which received patents.

Greenwood's earmuff factory closed in the wake of his 1937 death, but his legacy (and now-ubiquitous winter headgear) lives on, thanks in part to chilly Mainers. While the official holiday is December 21, Farmington residents follow the state legislature’s instructions “to observe [Chester Greenwood Day] in suitable places with appropriate ceremony and activity” on the first Saturday in December—closer to Greenwood's birthday of December 4—with parades and winter activities.

[h/t Associated Press]