April weather forecast
Surabaya, Indonesia

In April, the weather in Surabaya transitions further towards a drier season. There is a decline in rainfall and humidity compared to March, typical of the arrival of the dry season. The days are characterized by increased sunshine, but the comfortable temperatures persist. Recreational beach activities continue to thrill as sea temperature remains in favorable degrees, showing a slight increase from the previous month. By April's end, the wind speed decreases marginally, revealing calm outdoor conditions.

Temperature

The introduction of April notes a subtle temperature variation to a still hot 30.5°C (86.9°F) from March's 30.5°C (86.9°F). Surabaya, during April nights, records a temperature marginally cooler than the daytime average, at a moderately hot 25.6°C (78.1°F).

Heat index

During April, the heat index is evaluated at a fiery hot 38°C (100.4°F). Additional precautions are required to avert heat cramps and heat exhaustion. Persistent activity may culminate in heatstroke.
Take into consideration that the heat index values are calculated for shade and light wind conditions. Direct sunlight has the potential to heighten heat index values by 15 Fahrenheit (8 Celsius) degrees.
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 individual's temperature perception can be influenced by numerous factors such as metabolic variations, physical activity, and clothing. Awareness of direct sun exposure is crucial as it has the potential to heighten the weather's effects, pushing up the heat index by 15 Fahrenheit (8 Celsius) degrees. Heat index values are highly critical to babies and toddlers. Kids frequently fail to realize the necessity for resting and hydrating. Thirst is an advanced indication of dehydration - hence, maintaining hydration, especially during extended physical activities, becomes essential.
Perspiration and the resultant sweat evaporation are the body's natural thermostat, helping regulate temperature. When there is abundant moisture in the air, the body's cooling through the evaporation process becomes less effective, leading to the sensation of overheating. With body temperatures on the rise, inefficient heat shedding can lead to dehydration and its associated complications.

Humidity

In April, the average relative humidity in Surabaya is 76%.

Rainfall

In Surabaya, during April, the rain falls for 21.3 days and regularly aggregates up to 87mm (3.43") of precipitation. Throughout the year, in Surabaya, there are 187.8 rainfall days, and 839mm (33.03") of precipitation is accumulated.

Sea temperature

In Surabaya, Indonesia, the average seawater temperature in April is 29.6°C (85.3°F).
Note: Between 25°C (77°F) and 29°C (84.2°F), water temperature is typically considered very warm and pleasurable by everyone. Water activities at these temperatures are enjoyable for extended periods without discomfort.

Daylight

The average length of the day in April is 11h and 57min.
On the first day of the month, sunrise is at 05:31 and sunset at 17:33. On the last day of April, sunrise is at 05:30 and sunset at 17:21 WIB.

Sunshine

In Surabaya, the average sunshine in April is 9.1h.

UV index

January through December, with an average maximum UV index of 7, are months with the highest UV index in Surabaya. The months with the lowest UV index are January through December, with an average maximum UV index of 7. A UV Index value of 6 to 7 symbolizes a high threat to health from exposure to the Sun's UV radiation for ordinary individuals.
Note: In April, the maximum UV index of 7 translates into these guidelines:
Continue precautions and advocate sun safety advice. Deterrence of sunburn is indispensable. Make an effort to avoid direct sun exposure between 10 a.m. and 4 p.m., the peak period for UV radiation, and note that objects like parasols or canopies might not offer full sun protection. For excellent sun protection for the eyes, ears, face, and neck, consider a wide-brim hat. Caution! The Sun's UV intensity grows with reflections off sand and water.