Key Facts
• July 19 marks the start of a three-day weekend with widespread summer skies.
• Temperatures are expected to rise nationwide, with highs exceeding 35°C in some areas.
• Afternoon thunderstorms and sudden weather changes are likely, especially on July 20-21.
• July 19: Northern Tohoku declared the end of the rainy season, completing the nationwide transition.
• Pacific high pressure dominates, bringing strong sunlight across most regions except Hokkaido.
• July 20-21: Thunderstorms are highly probable in Kanto-Koshin, Tokai, and southern Tohoku.
• Heavy rain in Hokkaido may cause landslides and river flooding; caution advised until July 20 morning.
• Outdoor activities near mountains and rivers require vigilance for heatstroke and weather shifts.
• Key signs of upstream flash floods: rising water levels, murky water, and floating debris.
• Dam release sirens signal immediate evacuation from riverbanks.
Summary
The three-day weekend starting July 19 brings intense heat and unstable weather across Japan. With temperatures exceeding 35°C in many areas, heatstroke prevention is critical. Afternoon thunderstorms are expected, particularly in Kanto-Koshin, Tokai, and southern Tohoku on July 20-21. Hokkaido faces heavy rain risks, with potential landslides and flooding. Outdoor enthusiasts should monitor weather changes and stay alert for upstream flash flood signs. Ensure safety by avoiding riverbanks during dam release sirens.
