The annual monsoon season is forecast to start south of the peninsula from Jeju Island around Friday.

The Korea Meteorological Administration(KMA) said on Monday that a stationary front is gradually moving northward as a cold air system weakens and high pressure from the North Pacific begins to expand.

The KMA predicted that the onset of the rainy season will begin for southern parts of the country, including the Jeolla regions, between Sunday and Monday, before expanding into the central Chungcheong region by next Wednesday and Thursday.

It warned the monsoon season is expected to kick off with heavy showers from the combined effects of the stationary front and low pressure system.
 
The weather agency, however, said there are variabilities that could change the forecast due to a low pressure system coming in from the country's west.