Weather agency to extend forecasts to two weeks

By the Editorial Team · Saturday, August 29, 2026

The Japan Meteorological Agency announced plans to extend its detailed weather forecasts from five days to up to two weeks and update temperature comparison methods by 2030. These changes aim to enhance disaster preparedness, public health responses, and support industries affected by increasingly frequent extreme weather events due to climate change.

The Japan Meteorological Agency (JMA) is preparing to extend the scope and accuracy of its weather forecasts, aiming to provide detailed predictions up to two weeks in advance, officials announced. This move, the first significant update in three decades, is intended to help individuals and businesses better prepare for increasingly frequent extreme weather events across Japan.

An expert panel assembled by the JMA recently released a report recommending that, due to advances in climate data observation and simulation technology, the agency should extend its detailed daily forecasts from the current five-day period to 14 days. In addition, the report suggests extending warnings for heavy rainfall and snowfall events, which currently cover a five-day window, out to two weeks.

The proposal comes in response to the rising number of weather-related incidents in recent years. The agency highlighted last year’s record surge in ambulance calls linked to heatstroke and historic rainfall levels in Kumamoto Prefecture as examples of the growing impact of severe weather. The report emphasized the increasing importance of mid- to long-range weather information as a form of “soft infrastructure” that supports climate change adaptation efforts.

Apart from expanding the forecast period, the JMA plans to revise how it presents monthly temperature forecasts. Currently, the agency compares expected temperatures against a 30-year average, typically indicating whether they will be “higher” or “lower” than normal. The new approach would reference more recent periods, such as the past three years, to provide temperature comparisons that more accurately reflect current climate conditions and individuals’ actual experiences.

Officials noted that the enhanced forecasts could significantly improve disaster preparedness and public health responses to heat-related illnesses. Furthermore, industries reliant on weather conditions, such as manufacturing, transportation, and energy sectors, could benefit from more precise and longer-term information for scheduling and ensuring stable power supply.

The JMA plans to implement these improvements by 2030, marking a major step forward in Japan’s capability to forecast and respond to evolving weather patterns amid global climate change.

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