September weather forecast
Vanimo, Papua New Guinea

September rings in with slight variations in temperature, while the rainfall observes a decrease compared to August. Precipitation reduces to a low point again, similar to May levels. The sun shines for a nearly constant time, restricting sudden changes in temperature. However, despite diminished rainfall, the ocean remains warm, inviting for water-based activities. Natural scenery captures its best form during this period due to the generous sunshine.

Temperature

September's onset brings an average high-temperature of a still warm 29.1°C (84.4°F), nearly the same as August. Vanimo nights in September witness a mild cool down to an average temperature of 24.7°C (76.5°F).

Heat index

The heat index value during September is computed to be a fiery hot 35°C (95°F). Heightened safety actions are necessary, heat cramps and heat exhaustion are probable. Persistent activity may lead to heatstroke.
Data suggests that the heat index is set for environments in shade and with a light wind. Facing direct sunlight may hike up the heat index by 15 Fahrenheit (8 Celsius) degrees.
Note: The heat index, also known as 'apparent temperature' or 'felt air temperature', provides an understanding of perceived warmth by combining temperature and relative humidity. Elements such as metabolic variations, being pregnant, and physical activity can impact one's weather perception. When exposed to direct sunlight, it's possible for the heat index to increase by as much as 15 Fahrenheit (8 Celsius) degrees. Heat index values are particularly meaningful for babies and toddlers. Children are often less aware of the need to rest and re-hydrate. Thirst is a late sign of dehydration - it's vital to remain hydrated, particularly during prolonged physical activities.
The human body has a built-in cooling mechanism through perspiration; evaporating sweat dissipates the excess heat. When the air contains significant moisture, the efficiency of the evaporation process decreases, preventing the body from cooling down effectively and creating a feeling of overheating. Rising body temperatures due to excess heat retention could signify impending heat disorders.

Humidity

The months with the lowest humidity are September and October, with an average relative humidity of 79%.

Rainfall

September is the month with the least rainfall. Rain falls for 19.9 days and accumulates 61mm (2.4") of precipitation.

Sea temperature

In Vanimo, the average seawater temperature in September is 29.3°C (84.7°F).
Note: Swimming, diving, and other water endeavors at temperatures between 25°C (77°F) and 29°C (84.2°F) are considered enjoyable and satisfying for extended periods without discomfort.

Daylight

In Vanimo, the average length of the day in September is 12h and 6min.
On the first day of the month, sunrise is at 06:32 and sunset at 18:36. On the last day of September, sunrise is at 06:20 and sunset at 18:28 +10.

Sunshine

The average sunshine in September is 8.5h.

UV index

February through November, with an average maximum UV index of 7, are months with the highest UV index. A UV Index estimate of 6 to 7 represents a high health vulnerability from unsafe exposure to UV radiation for ordinary individuals.
Note: The maximum daily UV index of 7 in September converts into the following recommendations:
Follow precautions and abide by sun safety rules. Deterrence of sunburn is imperative. Stay in the shade and limit direct sun exposure between 10 a.m. and 4 p.m., when UV radiation is at its strongest. Remember, however, that not all shade structures provide full sun protection. Using UVA and UVB-protective sunglasses and sun-protective clothing is effective against UV radiation. Notice! The Sun's UV exposure elevates with sand and water reflections.