On Wednesday, April 18, rain is anticipated throughout South Korea, with snowfall forecasted for the northeastern regions of Gyeonggi and Gangwon. The Korea Meteorological Administration warns that rain will primarily affect southern Gyeonggi, Chungcheong, Jeolla, western Gyeongsang, and Jeju Island from early morning, gradually expanding to most areas by late morning. While the rain is expected to taper off by late afternoon in many regions, coastal areas of Gyeongnam and Jeju may continue to experience rain into the night, necessitating caution on slippery roads and reduced visibility.

Expected precipitation varies across the country, with estimates of 5 to 30 mm in many areas, notably up to 60 mm in mountainous regions of Jeju. Snow is also predicted in high-altitude areas of Gangwon, with accumulations of 1 to 5 cm possible. The forecasted daytime high temperatures range from 9 to 14 degrees Celsius, aligning closely with the seasonal averages. Detailed regional temperatures include highs of 11 degrees in Seoul and Chuncheon, 14 degrees in Busan, and 12 degrees in Daegu, with overall temperatures expected to be similar or slightly lower than average in the following days.

Additionally, strong wind gusts are projected for Jeju from the morning until the following day and in the Gangwon mountain areas and east coast in the early hours of April 19, reaching speeds of approximately 15 m/s. Therefore, precautions for facilities and safety in these areas are advised. Air pollution levels are particularly concerning today, with regions including the capital area, Gangwon Yeongseo, Sejong, Chungbuk, Chungnam, and Jeonbuk classified as experiencing 'bad' fine dust levels. The forecast indicates that areas like Seoul and southern Gyeonggi will potentially experience 'very bad' conditions in the morning, highlighting the ongoing issue of air quality in South Korea.