By Bae Keun-min
Staff Reporter

Unusually hot weather, which started Wednesday, is expected to continue Saturday, pushing the mercury to a daytime high of over 30 degrees in Celsius across the nation.

The Korea Meteorological Administration (KMA) said Friday the summer-like weather will peak Saturday, and rain will bring a recess to the hot weather on Sunday.

Most regions in the nation reported daytime highs of 25-32 degrees Celsius on Friday afternoon, some 5-6 degrees higher than average temperature.

The mercury in Kochang in South Kyongsang Province jumped to 31.1 degrees, while Seoul marked 25.3 degrees, the highest this year, the KMA said.

On Thursday, Yongdok in North Kyongsang Province marked a daytime high of 34 degrees, a record for April since 1904, when the official weather survey started.

The previous record was 33.6 degrees in Kangnung on April 20, 1998.

The current hot spell has appeared due to the moving of warm high atmospheric pressures located in China and the southern North Pacific Ocean to the peninsula, the weather agency said.

Meanwhile, local researchers said Seoul’s overall summer days have been extended by 20 days over the last 100 years while winter has shortened by 30 days.

According to research led by Seoul National University professor Kang In-shik, forsythia and azalea, symbols of spring, came into bloom between April and May before 1950. But their blooming season has advanced to February and March.

In addition, the Han River was frozen throughout the winter in the past. Now, the number of days that the river froze over during the winter was less than 10.

One year, in fact, the river did not freeze over once, the study said.

The number of days with frost also declined from 190 days to 150 days per year.

``There has been a steep rise in temperatures since the 1980s, resulting in a decrease in the number of days of frost and the Han River freezing. Seasons and botanical environments are also rapidly changing,’’ Kang said.

kenbae@koreatimes.co.kr