Guide 07 · Month context
Japan in September: compare five major observatories
September’s long-term figures show why a national monthly summary can conceal meaningful city differences. This table is not a storm forecast or disruption guide.
September climate normals
| Observatory | Mean °C | Daily high °C | Daily low °C | Precip. mm | Sun h |
|---|---|---|---|---|---|
| Sapporo | 18.6 | 22.8 | 14.8 | 142.2 | 159.3 |
| Tokyo | 23.3 | 27.5 | 20.3 | 224.9 | 126.7 |
| Osaka | 25.2 | 29.5 | 21.9 | 152.8 | 161.6 |
| Fukuoka | 24.7 | 28.6 | 21.6 | 175.1 | 164.7 |
| Naha | 27.9 | 30.6 | 25.8 | 275.2 | 181.3 |
A comparison, not an itinerary forecast
Among these stations, the listed September mean temperature ranges from 18.6°C in Sapporo to 27.9°C in Naha. Naha has the highest precipitation and sunshine-duration normal in this selected set, while Tokyo’s precipitation total exceeds the Osaka and Fukuoka totals shown here. Such observations describe a long-run monthly profile, not the sequence or severity of events in a future September.
Readers making time-sensitive plans should use current official information. The value of this page is that it makes the historical baseline, source and units visible before a general travel claim is made.
Source and limits. JMA Tables of Climatological Normals (1991–2020). This independent reference does not forecast storms or travel disruption.