Tokyo spent 35 days “drowning” in rain and NASA satellites watched every drop fall over Japan
For 35 days straight, Tokyo woke up to rain. From the final days of August through the last week of September 2026, the sky over central Japan simply refused to clear — a gray, unbroken stretch that turned the season’s rhythm on its head.
NASA satellites tracked it all in real time, capturing bands of rain sweeping across the region hour after hour. What they recorded raises a question worth asking: how does a city end up drowning for more than a month?
A record seven years in the making
Tokyo’s previous record for consecutive rainy days stood at 33 — set in June and July of 2019, when the city endured an unusually persistent wet stretch through early summer. That mark held for seven years. Then, between August 27 and September 28, 2026, the streak climbed to 35 days and rewrote the books.
NASA’s Worldview platform makes this kind of monitoring accessible, offering both current imagery and historical archives for tracking events like this one.
Breaking a rainfall continuity record in a megalopolis like Tokyo carries real weight. The city is home to roughly 14 million people within its core boundaries, and its infrastructure — drainage systems, transit networks, daily routines — is calibrated around seasonal norms. When those norms shatter, disruption compounds fast.
Worth noting: not every day in the streak was a downpour. Some registered only trace amounts of rain. But under meteorological standards, even minimal precipitation counts — and the continuity never broke. That uninterrupted thread is exactly what made 2026’s stretch historic.
25 inches in 35 days: Three times the norm
The numbers stand on their own. Over those 35 days, Tokyo accumulated 629 millimeters — roughly 25 inches — of rainfall. That’s approximately three times the normal precipitation for that stretch of the season.
In little more than a month, the city received what it would typically expect across an entire season. The single most intense day came on September 21, when 156 millimeters (6 inches) fell within 24 hours — a volume that would be noteworthy on its own, let alone embedded inside a five-week rain event.
Seasonal averages reflect decades of accumulated climate data. They shape how cities plan for water management, agriculture, and public safety. When a single event triples that baseline, it exposes the limits of planning built around what used to be normal.
Typhoons Krovanh and Dujuan: The streak’s most intense moments
Sustained rainfall over 35 days doesn’t mean uniform rainfall. Within the streak, two typhoons — Krovanh and Dujuan — drove the most extreme precipitation episodes, and the peak on September 21 coincided with the passage of one of these systems.
Typhoons approaching or making landfall near Japan can dramatically intensify ongoing rainfall events. Their spiral bands push enormous volumes of moisture inland, often interacting with existing weather patterns to produce concentrated, heavy precipitation over short periods. Here, they transformed an already unusual wet stretch into something far more extreme.
Many days saw moderate or minimal rain — enough to keep the record alive, but not enough to cause major disruption on their own. The typhoon-driven episodes were the outliers that pushed totals into record territory.
How NASA satellites watched every drop fall
While Tokyo residents tracked the rain from street level, NASA’s instruments were watching from orbit. The key tool was IMERG — the Integrated Multi-satellitE Retrievals for Global Precipitation Measurement — which measures rainfall rates in millimeters per hour across wide geographic areas, providing a continuous, quantified picture of storm bands moving over central Japan.
Layered on top were true-color images from the VIIRS instrument aboard the NOAA-20 platform. VIIRS captures visible-light imagery, giving scientists and the public a recognizable, photographic-style view of cloud systems and storm structure.
Combining precipitation rate data with optical imagery creates something more useful than either dataset alone. You can see where rain is falling and how intensely — in near real time. NASA’s Worldview platform makes this kind of monitoring accessible, offering both current imagery and historical archives for tracking events like this one.
What a record like this is really asking
Records are data points. But they also ask questions. When a city like Tokyo — with sophisticated infrastructure and well-documented climate history — sees its rainfall continuity record broken by two full days, it’s worth pausing on what that signals.
Events of prolonged, extreme precipitation may not remain statistical outliers for long. As climate patterns shift, the boundary between “unusual” and “expected” tends to move — sometimes faster than planners anticipate. Satellite monitoring systems like IMERG and Worldview become more valuable precisely because they can track that movement, helping cities anticipate risks rather than simply react after the fact.
Whether a 35-day streak becomes a new benchmark or an early warning is a question Tokyo, and cities like it, may have to answer sooner than expected.
Daniel García is an Editor-in-Chief with strong expertise in structural work and engineering principles. He combines this technical foundation with deep knowledge of energy, spatial design, and emerging technologies, bringing a forward-thinking and analytical approach to editorial leadership.
