On January 18, marking the last day of the Lunar New Year holiday, the weather across South Korea is expected to be mostly clear and warm during the day, with temperatures ranging from 5 to 13 degrees Celsius. However, in the morning, most regions, except the southern parts, will experience temperatures dropping to below freezing, with the lowest forecasted temperatures between -7 and 3 degrees Celsius. High winds will exacerbate the cold, leading to even lower perceived temperatures.

Dry weather conditions are particularly concerning along the eastern coast and mountainous areas, necessitating increased vigilance against the risk of wildfires. Wind speeds are expected to reach around 55 km/h (15 m/s) along the eastern coast, with gusts in mountainous areas potentially escalating to 70 km/h. The forecast also anticipates light rain in Jeju Island overnight, with conditions improving throughout the morning.

For detailed regional forecasts on January 18, clear weather is anticipated with specific temperature ranges: Seoul (0-6°C), Incheon (1-5°C), Suwon (-1-6°C), and various other cities displaying similarly cold morning temperatures with warmer afternoons. The sea conditions will vary, with wave heights in the East Sea between 0.5 to 3.5 meters, suggesting a variable marine environment that may influence coastal activities.