September weather forecast
Yap, Micronesia

September is another month associated with significant rainfall in Yap, with an average rainfall of 343mm (13.5") recorded. Nevertheless, compared to August, the declining rainfall signals a transition towards drier eras. Temperatures remain steady, and the sea temperatures continue to be warm, making marine activities pleasurable. The decrease in rainfall from its August peak also leads to an increase in sunshine duration, enhancing the potential for outdoor exploits. The transition phase from the wetter months to the less rainy ones brings an exceptional charm to September's weather.

Temperature

Yap's average high-temperature in September is a still tropical 30.9°C (87.6°F), indicating a subtle variation from August. Yap, during the nights of September, experiences an average temperature drop to a moderately hot 23.5°C (74.3°F).

Heat index

During September, the heat index is estimated at a blisteringly hot 42°C (107.6°F). Undertake additional precautions, heat cramps and heat exhaustion could happen. Heatstroke could occur from sustained activity.
When referencing the heat index, its values are suitable for shady environments and light breezes. Direct sunlight might cause an increase of up to 15 Fahrenheit (8 Celsius) degrees in the heat index.
Note: The heat index, also known as 'real feel' or 'felt air temperature', joins air temperature with relative humidity to produce a temperature perception for humans. The effect of weather is individual, with a variety of people experiencing it differently due to distinctions in body mass, height, and level of activity. Remember, direct sunlight exposure can heighten the heat impact and might increase the heat index by 15 Fahrenheit (8 Celsius) degrees. Heat index values are highly important for children. Children often overlook the need for breaks and fluid intake. Thirst is a late-stage sign of dehydration - hence, it is necessary to stay hydrated, especially during extended periods of physical activities.
Perspiring is the body's way of cooling down, particularly by allowing sweat to evaporate and take the heat with it. A higher relative humidity affects normal body cooling by reducing the evaporation rate, subsequently lowering the rate at which the body cools and increasing the perception of heat. If heat absorption isn't effectively countered by the body's cooling methods, body temperature surges, hinting at potential problems.

Humidity

The months with the highest humidity are July through October, with an average relative humidity of 84%.

Rainfall

In September, the rain falls for 19.3 days. Throughout September, 343mm (13.5") of precipitation is accumulated. In Yap, during the entire year, the rain falls for 211.6 days and collects up to 3050mm (120.08") of precipitation.

Sea temperature

The months with the warmest seawater in Yap are May through December, with an average sea temperature of 29°C (84.2°F).
Note: Ideal surface water temperatures for any water activity fall between 25°C (77°F) and 29°C (84.2°F), offering maximum enjoyment for lengthened periods.

Daylight

The average length of the day in September is 12h and 11min.
On the first day of the month, sunrise is at 06:38 and sunset at 18:56. On the last day of September, sunrise is at 06:35 and sunset at 18:38 +10.

Sunshine

In September, the average sunshine is 6h.

UV index

The months with the highest UV index are February through October, with an average maximum UV index of 12. A UV Index reading of 11, and higher, represents an ultimate health vulnerability from exposure to the Sun's UV radiation for the average person.
Note: The maximum UV index of 12 during September translates into these guidelines:
Execute every important safeguard, as unprotected skin and eyes could burn within moments. 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. Enhance your sun protection with tightly woven, yet airy clothing. Even if the day is cloudy, sunscreen with SPF of at least 30 should be applied generously and reapplied often, particularly after swimming or outdoor exercise. Beware! Reflections from sand and water can intensify the Sun's UV radiation.