Japan Meteorological Agency Warns of Hot Summer and Winter Due to El Niño

The Japan Meteorological Agency said Wednesday that El Niño conditions have been occurring since spring 2026, signaling unusually hot weather for the country [1, 2].

This shift is significant because it contradicts historical trends where El Niño typically leads to cooler summers in Japan ^[4]. The agency said that both the upcoming summer and winter are expected to be unusually hot nationwide [1, 2].

According to the agency, sea-surface temperatures in the equatorial Pacific, stretching from the coast of Peru to the central Pacific, were approximately 1.2 °C above the long-term average in May ^[1]. This warming indicates the onset of the El Niño phenomenon [1, 2].

Masayuki Kyoda, director at the agency, said the phenomenon has likely been occurring since spring. He urged the public to prepare for the heat, saying, "We expect high temperatures to be brought about, so please prepare for the heat."

Experts note that enhanced convection east of the Philippines is expected to strengthen the Pacific high-pressure system over Japan [1, 2]. This atmospheric shift is the primary driver behind the forecast for higher temperatures during both the summer and winter seasons [1, 2].

Reports on the timing of the previous event vary. Some sources state this is the first occurrence in three years ^[1], while others describe it as returning after approximately two years ^[2]. Regardless of the exact interval, the current conditions suggest a high probability of impact. One forecast indicated a 90% probability of El Niño occurring during the 2026 summer ^[3].

While the general historical tendency for El Niño is a cooler summer, the agency said that this year will likely see a nationwide trend toward high temperatures ^[2].