60% of rain forecasts wrong during Seoul's rainy season

Nearly two-thirds of South Korea's weather agency's forecasts for Seoul during the rainy season this year were incorrect, data showed Thursday.

Rep. Lim Lee-ja of the ruling People Power Party analyzed Korea Meteorological Administration's rain forecast for Seoul from June 29 to July 27, and compared it to the actual weather in the South Korean capital. The KMA predicted rain for 27 of the 29 days.

Lim found that of the 27 days it was supposed to rain, forecasts for 16 of these days were inaccurate. Specifically, rain was completely absent or far below the minimum predicted amount on 11 days, and less than half the maximum predicted on four days.

For the remaining one day, the precipitation for the city was more than twice the maximum that had been predicted.

The official accuracy rate for the KMA remains in the high 70-percent or low 80-percent range. But the figure only takes into account whether or not it rained that day, not whether the agency accurately predicted the precipitation.

For example, the forecast for Seoul predicted 30 to 80 millimeters of rain in Seoul July 4-5. But the actual precipitation was between 2 and 23 millimeters. Technically, the KMA was right in forecasting rain, but not accurate in predicting how much.

The overall accuracy of KMA weather forecasts has been declining in recent years. The month of July typically has the most precipitation, and the accuracy rate for it has fallen from 83.8 percent in 2022 to 78.2 percent in 2023, and 77 percent this year.