Korea uses both the lunar and solar calendars, even though Most Korean calendars have small prints of lunar dates in reference to the solar dates. The country uses one time zone and is 9 hours ahead of GMT, the same as Japan. Most Koreans work Monday through Friday. Usual business hours are 9:00am-6:00pm. During the national holidays, government offices and most businesses are closed, although many private store keepers and large department stores may remain open. The major exceptions occur during the 3-day holidays for the Lunar New Year (Seollal) and Harvest Moon Festival (Chuseok) when just about everything shuts down except public transportation.
 

Official Korean Holidays

• New Year's day : January 1st
  The first day of New year is celebrated.
• Seollal : January 1st (on the Lunar Calendar)
  This is the biggest holiday in Korea for celebrating the new year's day of the lunar calendar. Officially it is a three-day celebration, but some companies or stores take off more days. People visit their relatives and hometown, pay offerings to their ancestors and feast. Younger ones bow to their elders.
• Sam-il-jeol (Independence Movement Day) : March 1st
  This is to commemorate the nation-wide uprising against Japanese colonialization of Korea on March 1st, 1919.
• Buddha's Birthday : April 8th (on the Lunar Calendar)
  Buddhism was introduced into Korea in the 4th century, and from the ancient Three Kingdom age through Goryo, it was Korea's national religion. Therefore, it has tremendous cultural influence on Korea.
• Children's Day : May 5th
  On this day, well-dressed children enjoy a full day of fun and games with their parents at amusement parks, zoos and etc.
• Memorial Day : June 6th
  This is to honor the soldiers and civillans of saving the country.
• Independence Day : August 15th
  On August 15th, 1945, Korea was liberated from Japanese colonialization.
• Chuseok : August 15th (on the Lunar Calendar)
  Along with Seollal, this is the biggest holiday in Korea. It is to express gratefulness to ancestors for the harvest of the year. It is a three-day celebration, in which people go back to their hometown to meet their parents and pay a visit to their ancestor's graves.
• National Foundation Day : October 3rd
  This is to commemorate the foundation of Gojoseon, the first country in the Korean peninsula by Dan-gun-wang-gum in 2333 B.C.
• Hangeul Day (Korean Alphabet Day) : October 9th
  This is to commemorate the creation of Hangeul, Korea's native alphabet as proclaimed by the publication of Hunminjeongeum on this day in 1446.
• Christmas : December 25th