Japan experienced extreme and contradictory weather patterns on Monday, May 4, 2026, with simultaneous heatwaves and heavy snowfall across the archipelago.

These volatile conditions disrupted travel and daily life during the first day of the Golden Week holiday period, highlighting the instability of regional weather patterns.

In Tokyo, the Nerima district recorded a maximum temperature of 30.5 °C [1]. This surge in heat occurred while northern regions faced a sudden cold air mass. In Hokkaido, Kushiro City experienced an unseasonal snowfall that reached up to 21 cm [2].

The temperature disparity was stark across the country. In Miyagi, the temperature at Goshō was recorded at 3 °C [1]. Reporter Taro Miyashiro said that while visitors usually see beautiful scenery from that location, they were unable to do so on Monday.

One tourist said that while it was hot in Osaka, the conditions in Yamagata and Miyagi were very cold with significant fog.

Strong winds accompanying a low-pressure system caused significant transport disruptions. The Tokyo Bay Aqua-Line was closed for 15 hours [1]. Other impacts were reported at Narita Airport, the Odakyu line in Kanagawa, and in Shira… in Wakayama [1], [2].

The mixed weather was driven by a low-pressure system that pushed a cold air mass into northern Japan while triggering a heat surge in the south [3].

“Nerima recorded a 30.5 °C temperature, Kushiro experienced an unseasonal snowfall of up to 21 cm”

The simultaneous occurrence of summer-level heat in Tokyo and heavy May snowfall in Hokkaido suggests an increase in atmospheric instability. When extreme temperature gradients exist across a single geographic region, it often leads to the high-wind events and transport failures seen with the Tokyo Bay Aqua-Line closure.