September weather forecast
Gresik, Indonesia

The first month of the spring, September, is also a hot month in Gresik, Indonesia, with temperature in the range of an average low of 24.3°C (75.7°F) and an average high of 32.6°C (90.7°F).
The ideal sea water temperature of 28.1°C (82.6°F) and only 2.9 rainfall days, with 3mm (0.12") of accumulated rainfall, makes September the best time for swimming and other water activities.

Temperature

The advent of September in Gresik denotes an average high-temperature of a still hot 32.6°C (90.7°F), subtly different from August's 31.8°C (89.2°F). Gresik's temperature lowers to a mean of 24.3°C (75.7°F) during the nights in September.

Heat index

The heat index for September is computed to be a blistering 40°C (104°F). Take more caution, heat exhaustion and heat cramps may occur. Long-lasting activity may cause heatstroke.
Records show heat index calculations are tailored for shaded regions and mild winds. Uninterrupted exposure to the sun may boost the heat index values by 15 Fahrenheit (8 Celsius) degrees.
Note: The heat index, also known as 'real feel' or 'feels like', is an indicator that blends the effects of temperature and humidity to depict perceived warmth. The experience of temperature can be subjective, varying based on the individual's activity and heat perception, influenced by factors like wind, attire, and metabolic variations. Being under direct sunshine can magnify the heat experience, possibly pushing up the heat index by 15 Fahrenheit (8 Celsius) degrees. Heat index values are particularly relevant to babies and toddlers. Children often fail to understand the importance of rest and rehydration. Thirst is a late manifestation of dehydration - hence, it is crucial to stay hydrated, especially during ongoing physical activities.
One of the main methods the human body employs to cool down is by perspiring, as this process allows sweat to evaporate and remove excess heat. In the presence of abundant moisture in the atmosphere, the cooling process through evaporation is hindered, causing the body to feel excessively warm. When body temperature rises due to an imbalance in heat gain, there's a potential for dehydration and overheating.

Humidity

The months with the lowest humidity in Gresik, Indonesia, are September and October, with an average relative humidity of 63%.

Rainfall

The months with the least rainfall in Gresik are August and September Rain falls for 2.9 days and accumulates 3mm (0.12") of rain.

Sea temperature

In September, the average sea temperature in Gresik is 28.1°C (82.6°F).
Note: Water temperature ranging between 25°C (77°F) and 29°C (84.2°F) is considered very warm and pleasing for everyone. It allows for enjoyable water activities over extended periods without discomfort.

Daylight

In Gresik, Indonesia, the average length of the day in September is 12h and 4min.
On the first day of September in Gresik, sunrise is at 05:29 and sunset at 17:28. On the last day of the month, sunrise is at 05:14 and sunset at 17:24 WIB.

Sunshine

August through October, with an average of 9.8h of sunshine, are months with the most sunshine in Gresik, Indonesia.

UV index

January through December, with an average maximum UV index of 7, are months with the highest UV index. January through December, with an average maximum UV index of 7, are months with the lowest UV index. A UV Index of 6 to 7 symbolizes a high health vulnerability from exposure to the Sun's UV radiation for the average person.
Note: The UV index of 7 during September translates into the following guidance:
Employ safeguards and advocate sun safety protocols. Shielding against skin and eye damage is crucial. Avoid direct Sun exposure and stay in the shade between 10 a.m. and 4 p.m., a time when UV radiation is most intense, noting that not all shade structures offer full protection. For a sun-safe wardrobe, go for clothes that are tightly woven and generously sized. Caution! Sand and water surfaces escalate the UV intensity from the Sun.