It was originally to run from October 1st through the 12th. I've gone the past two years, and not only was it interesting during the day---unlike a lot of festivals, admittedly---but it was especially beautiful at night. On a post last fall I collected some pictures from around the wire:
Over a million people attended the festival on the opening three-day weekend last year, and the year before there were an estimated three million during the two-week run. Granted, it is in celebration of killing Japanese people:
Jinju Namgang Yudeung Festival has its origin from the Jinjuseong battles in the worst suffering period of Imjinwaeran(Japanese Invasion). In October, 1592, when General Kim Si-min with his 3,800 men killed 20,000 Japanese troops, heightening national pride, the lanterns were used not only as military signals but also communicative methods between soldiers and their families.
In the 2nd attack in June, 1593, 70,000 citizens, officials and soldiers were killed, and after it, they began to float the lanterns on the river during Gaecheon Art Festival as a service for repose of the deceased and peace and prosperity of homes and nation.
Reflecting the long history of Jinju, Jinju Namgang Yudeung Festival has settled as the symbol of royalty and wishing.
There have been several big festival cancellations this fall, including the Andong Mask Dance Festival, the Gwangju Kimchi Festival, and, as norepeat tells us, the Seoul International Fireworks Festival. Others have told me about others in the comment sections, and I'll do my best to pass along word of the big ones locally and nationally. As I wrote before, though, if you made plans to attend festivals this fall, you'd better make back-up plans. Browsing the "Festivals" and "Swine flu in Korea" categories will bring you the round-up.