The Japan Meteorological Agency (JMA) issued a new one-month weather forecast on May 28, indicating that Japan will face a sustained period of higher-than-average temperatures. As the nation transitions into early summer, residents are being urged to prepare for a dual threat: the potential for significant heat-related illness and the risk of heavy rainfall in specific regions.
A Period of Unusual Heat
Beginning around June 3, a significant portion of the country—specifically from the Tokai region through Kyushu—is expected to experience temperatures that are rare for this time of year. The JMA has issued an “Early Warning Information on Extreme Weather,” noting that the region could see temperatures that historically occur only once every decade.
This trend is linked to lower-than-average atmospheric pressure near the Sea of Okhotsk, which is expected to facilitate the inflow of warm air across the Japanese archipelago. While the entire country is likely to see elevated temperatures, the western parts of Japan, as well as Okinawa and Amami, are expected to experience particularly intense heat throughout the upcoming month.
Rainfall and the Approaching Rainy Season
While heat dominates the forecast, the Pacific side of eastern and western Japan faces a different concern. Due to the influence of Typhoon No. 6 and moist air currents, precipitation levels in these areas are likely to be equal to or higher than the seasonal average over the next month. Residents are advised to monitor the movement of typhoons and weather fronts closely, as they could trigger localized heavy rainfall.
Meanwhile, the onset of the rainy season is expected to arrive later than usual this year across the country, from Kyushu to the Tohoku region. As the transition to the rainy season approaches, meteorologists recommend utilizing dry, clear days to clear gutters and drainage ditches to mitigate potential flood risks during heavy downpours.
Looking Ahead
As temperatures climb, the humidity is also expected to rise, increasing the discomfort index and the danger of heatstroke. In the coming weeks, if “Heatstroke Alert” notifications are issued, residents may need to adjust their daily routines by limiting time spent outdoors and seeking cool environments during the hottest parts of the day.
Frequently Asked Questions
What should I do to prevent heatstroke during this period?
In addition to staying hydrated, it is important to replenish salt, especially on days when you are sweating significantly. Using air conditioning appropriately and avoiding the outdoors during peak temperature hours is also strongly advised.
Is the rainy season expected to start on time this year?
No, current forecasts suggest that the rainy season will likely begin later than the historical average across the region from Kyushu to Tohoku.
Which regions are most at risk for heavy rain?
The Pacific side of eastern and western Japan is expected to see precipitation that is either average or higher than average over the next month, largely due to the impact of Typhoon No. 6 and incoming moist air.
How are you preparing your home and personal health for the early arrival of intense summer heat?
