September weather forecast
Okayama, Japan

September marks the descent from peak summer with a mild drop in temperature, reaching 28.4°C (83.1°F). There is a resurgence in rainfall, rising to 134mm (5.28") in preparation for the upcoming autumn season. The dropping temperatures and humidity mark a transition toward more comfortable surroundings. This changing weather adds a new layer of color to the city's landscape as the leaves start to change. The sunsets in Okayama during this shift of seasons are truly breathtaking, creating a beautiful palette across the sky.

Temperature

The transition to September results in a modest reduction in average high-temperature, moving from a hot 32.7°C (90.9°F) in August to a warm 28.4°C (83.1°F). In September, the temperature drops to an average of 20.7°C (69.3°F) at night.

Heat index

In September, the heat index is computed to be a tropical 31°C (87.8°F). If activity and exposure persist, they could induce fatigue, leading to possible heat cramps.
Remember that heat index calculations are made for conditions in the shade with light wind. Direct exposure to sunlight could raise the heat index by 15 Fahrenheit (8 Celsius) degrees.
Note: The heat index, also known as 'felt air temperature' or 'apparent temperature', blends air temperature and moisture content to represent the felt temperature to humans. The individual's experience of temperature can be shaped by numerous aspects such as metabolic variations, physical exertion, and attire. You should know that direct sun exposure can heighten weather effects, potentially elevating the heat index by 15 Fahrenheit (8 Celsius) degrees. Heat index values are extremely significant for children. In general, children are more at risk than adults because they sweat less. Furthermore, the large skin surface compared to their small bodies and the high heat production due to their actions contribute to this vulnerability.

Humidity

The average relative humidity in September is 70%.

Rainfall

In Okayama, in September, it is raining for 17 days, with typically 134mm (5.28") of accumulated precipitation. In Okayama, Japan, during the entire year, the rain falls for 189 days and collects up to 1106mm (43.54") of precipitation.

Snowfall

April through December are months without snowfall in Okayama.

Sea temperature

In September, the average sea temperature in Okayama, Japan, is 25.8°C (78.4°F).
Note: For any water activity, surface water temperatures between 25°C (77°F) and 29°C (84.2°F) are considered as excellent and extremely pleasant for lengthened periods.

Daylight

The average length of the day in September is 12h and 24min.
On the first day of September, sunrise is at 05:37 and sunset at 18:31. On the last day of the month, sunrise is at 05:58 and sunset at 17:50 JST.

Sunshine

The average sunshine in September in Okayama is 5.2h.

UV index

In Okayama, the average daily maximum UV index in September is 8. A UV Index estimate of 8 to 10 represents a very high health hazard from exposure to the Sun's UV radiation for ordinary individuals.
Note: The maximum UV index, 8 during September, leads to the following recommendations:
Always be cautious. Skin and eyes can be affected swiftly without protection. Avoid direct Sun exposure from 10 a.m. to 4 p.m., a period when UV radiation is most intense, and remember that not all shade structures provide full protection. Sun protection is enhanced with clothing that boasts a tight weave yet offers a loose fit. Caution! The reflection of sand and water significantly amplifies the Sun's UV radiation.