September weather forecast
Ishigaki, Japan

September reveals a subtle transition from the wetter August, while temperatures begin to slightly decline. Wind speeds also increase during this month, reaching an average of 25.1km/h (15.6mph), which can provide some relief from the humidity. Despite it being a slightly wetter month, the number of hours of daylight remains steadily high, allowing tourists ample exploration time. Although temperatures start to fall, the sea maintains a consistent warmth of 29°C (84.2°F), adding to the allure for underwater activities.

Temperature

The transition from August to September brings an average high-temperature of a still warm 28.5°C (83.3°F), barely different from August's 29.3°C (84.7°F). Ishigaki experiences a steady nighttime temperature of 27.5°C (81.5°F) throughout the month of September.

Heat index

September's mean heat index is appraised at a tropical 33°C (91.4°F). Apply extra caution, heat cramps and heat exhaustion could happen. Heatstroke might occur with long-duration activity.
Take into consideration that the heat index values are calculated for shade and light wind conditions. Heat index values might soar by up to 15 Fahrenheit (8 Celsius) degrees with exposure to direct sunshine.
Note: The heat index, also known as 'real feel' or 'felt air temperature', is a numerical representation of warmth when taking temperature and moisture levels into account. The impression of weather on a person can be swayed by additional aspects, including metabolic variations, pregnancy, and activity levels. Be mindful that being in direct sunlight might mean feeling hotter, with the heat index rising by up to 15 Fahrenheit (8 Celsius) degrees. Heat index values are especially crucial for babies and toddlers. Children often lack awareness of the importance of taking breaks and rehydrating. The feeling of thirst is a late indication of dehydration, so maintaining hydration, especially during long periods of physical activity, is critical.

Humidity

In September, the average relative humidity in Ishigaki, Japan, is 79%.

Rainfall

In Ishigaki, in September, during 19.3 rainfall days, 138mm (5.43") of precipitation is typically accumulated. In Ishigaki, during the entire year, the rain falls for 228 days and collects up to 1184mm (46.61") of precipitation.

Sea temperature

July through September, with an average sea temperature of 29°C (84.2°F), are months with the warmest seawater in Ishigaki.
Note: Water temperatures between 25°C (77°F) and 29°C (84.2°F) are ideal for swimming, diving, and other activities, ensuring comfort and enjoyment for lengthened periods.

Daylight

In Ishigaki, the average length of the day in September is 12h and 18min.
On the first day of the month, sunrise is at 06:24 and sunset at 19:01. On the last day of September, sunrise is at 06:34 and sunset at 18:31 JST.

Sunshine

In Ishigaki, the average sunshine in September is 8.3h.

UV index

May through September, with an average maximum UV index of 7, are months with the highest UV index in Ishigaki. A UV Index estimate of 6 to 7 represents a high threat to health from unsafe exposure to UV radiation for ordinary individuals.
Note: During September, 7 as the daily maximum UV index converts into the following advice:
Take precautions against overexposure. Protection against sun damage is needed. Stay in the shade and avoid direct Sun exposure from 10 a.m. to 4 p.m., a time when UV radiation is at its strongest, and remember that parasols or canopies do not offer full protection. Stay sun-safe with clothing that is both closely woven and worn loosely. Attention! The reflection of both water and sand can increase the intensity of UV rays.