Weather in Osaka-shi for September 2025

In September, Osaka, Japan experiences a transition from the hot and humid summer to a more temperate autumn. At the beginning of the month, the weather remains quite warm and humid, with average daytime temperatures around 28° to 30°.

Nights are slightly cooler but still relatively warm, averaging around 22° to 24°. The humidity can be quite high, often exceeding 70%, which can make the heat feel more intense.

Rain is also common in early September, as the tail end of the typhoon season can bring heavy showers and occasional storms.

As the month progresses, the weather starts to cool down gradually. By the end of September, daytime temperatures typically range from 24° to 26°, while nighttime temperatures drop to a more comfortable range of 18° to 20°.

The humidity levels also begin to decrease, making the air feel fresher and more pleasant. Rainfall becomes less frequent, although occasional showers can still occur.

Overall, September in Osaka is a month of change, moving from the intense heat of summer to the more moderate and enjoyable conditions of autumn.

Visitors should be prepared for a mix of warm and cooler days, and it’s advisable to carry an umbrella due to the unpredictable nature of the weather during this transitional period.