Rainy season to end this weekend, giving way to nationwide heat wave

This summer's rainy season is drawing to a close. As the monsoon retreats early next week, a full-scale heat wave is expected to grip the country. However, even after the rainy season ends, locally intense rainfall remains possible and warrants caution.

The Korea Meteorological Administration said at its regular forecast briefing Thursday that the rainy season on Jeju Island ended Sunday, and that the monsoon is expected to wrap up across central and southern regions between Saturday and Sunday.

Rain will fall on and off Friday and Saturday, mainly across the Greater Seoul area and Gangwon Province, with expected precipitation of 5 to 40 millimeters. Areas south of the Chungcheong region can expect scattered showers.

On Sunday, a stationary front will push southward, bringing rain centered on the central regions and parts of North Jeolla and North Gyeongsang provinces. Monday is forecast to bring the final monsoon rains to the Greater Seoul area and Gangwon Province. From Tuesday onward, the entire country will come under the influence of the North Pacific high-pressure system, in effect ending the rainy season.

If the rainy season ends as the Korea Meteorological Administration forecasts, the timing will be close to historical averages — July 20 for Jeju Island, July 24 for southern regions and July 26 for central regions. Jeju's end date would be nearly identical to the norm, while central and southern regions would finish only slightly later than usual.

Although the rainy season started late this year, its end date is close to the historical average, making it a relatively short monsoon season overall.

Once the rains clear, intense heat is expected to set in. By late next week, the North Pacific high-pressure system in the lower and middle atmosphere, on top of the Tibetan high in the upper atmosphere, will together blanket the Korean Peninsula, making a heat wave highly likely.

From Monday through Aug. 2, morning lows are forecast at 23 to 26 degrees Celsius and afternoon highs at 29 to 37 degrees — similar to or slightly above the historical averages of 22 to 25 degrees for lows and 29 to 33 degrees for highs.

However, the onset of a heat wave does not mean the risk of heavy rain disappears. The hot and humid North Pacific high can fuel locally intense rain bands, meaning sudden, concentrated downpours could strike at any time.

The Korea Meteorological Administration urged the public to "take thorough precautions against heat wave and tropical night conditions."