Yesterday (7/19) was Chobok (초복), marking the first of boknal (복날), which are the three hottest days of the year by the lunar calendar. In honor of the day, our boss (the illustrious Mr. Moon) generously donated a watermelon to the staff room, which we scarfed down during our last 5 minute break of the evening.
Although chicken is popular in Korea all year long, samgyetang (삼계탕; hot chicken soup with traditional medicinal herbs, including ginseng) is the most popular boknal dish. You might understand the concept ofiyeol chiyeol (이열치열; to relieve heat with heat) and accept the Korean custom of eating hot food in the summer. Understandably, Mr. Moon did not donate samgyetang to the staff room as this would have been even more difficult to scarf on the run.
Chobok is the first signal of the hot summer. The peak of the summer heat is jungbok and malbok is the last hottest day in summer. Usually each bongnal (boknal) comes at 10 day intervals. Koreans have a saying to "fight fire with fire" and usually eat hot foods to combat the summer heat during the bongnal (boknal) season. I just drink decaf hot coffee and hope for the best.
(Info shamelessly cribbed from nanoomi.net and prkorea.com)