January weather forecast
Surabaya, Indonesia

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The skyscrapers making the cityscape of Surabaya in East Java, Indonesia
The skyscrapers making the cityscape of Surabaya in East Java, Indonesia

Weather in January

The weather in Surabaya during the first onset of the year ushers in a warm milieu with adequate cloud cover that provides optimal conditions for outdoor activities. It is slightly warmer than December, which offers a hint of continuity in the holiday cheer. January experiences strong winds and high humidity levels, which is indicative of an active wet season with significant rainfall events. As the month with the highest recorded rainfall of 172mm (6.77"), it is prudent to keep an umbrella at hand. Intriguingly, despite the presumed gloomy skies, the month still experiences an above-average duration of sunlight.

Temperature

January, February and July are the coldest months, with an average high-temperature of 30.1°C (86.2°F).

Heat index

The average heat index in January is evaluated at a very hot 37°C (98.6°F). Greater preventive actions are needed, heat exhaustion and heat cramps are likely. Persistent activity could provoke heatstroke.
Consider that heat index readings are for situations in the shade and light wind. A direct sunlight exposure may boost the heat index by 15 Fahrenheit (8 Celsius) degrees.
Note: The heat index, also known as 'real feel' or 'felt air temperature', ties air temperature with relative humidity to produce the perceived temperature sensation. One's perception of temperature can vary depending on physical activity and individual heat sensitivity, influenced by factors like wind, attire, and metabolic variations. 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 quite important for children. Kids often lack the knowledge about the necessity to take breaks and consume liquids. Thirst, as a late symptom of dehydration, necessitates the maintenance of hydration, particularly during enduring physical activities.
Perspiration is the human body's physiological response to high temperatures and is an attempt to lower body temperature through evaporation of sweat. With an abundance of moisture present in the air, the process of evaporation becomes less effective, and the body fails to cool down as it should, leading to the sensation of overheating. As body temperatures escalate without effective heat release, one might face dehydration threats.

Humidity

In Surabaya, the average relative humidity in January is 78%.

Rainfall

In Surabaya, during January, the rain falls for 27 days and regularly aggregates up to 172mm (6.77") of precipitation. Throughout the year, in Surabaya, Indonesia, there are 187.8 rainfall days, and 839mm (33.03") of precipitation is accumulated.

Sea temperature

In Surabaya, Indonesia, the average seawater temperature in January is 29.3°C (84.7°F).
Note: For activities in the water such as swimming or diving, temperatures from 25°C (77°F) to 29°C (84.2°F) are considered optimal for prolonged enjoyment without discomfort.

Daylight

In Surabaya, the average length of the day in January is 12h and 29min.
On the first day of the month, sunrise is at 05:16 and sunset at 17:48. On the last day of January, in Surabaya, sunrise is at 05:29 and sunset at 17:55 WIB.

Sunshine

With an average of 8.1h of sunshine, January has the least sunshine of the year.

UV index

The months with the highest UV index in Surabaya are January through December, with an average maximum UV index of 7. January through December, with an average maximum UV index of 7, are months with the lowest UV index in Surabaya. A UV Index value of 6 to 7 symbolizes a high health hazard from unprotected exposure to Sun's UV rays for the average person.
Note: An average maximum UV index of 7 in January leads to these recommendations:
Stay clear of intense sun exposure. Solar protection is of utmost significance. 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. To best shield against UV radiation, choose sun-safe garments and dependable sunglasses. Notice! The reflection of water and sand increases the UV radiation significantly.

Frequently asked questions

What is the coldest time of year in Surabaya?

In Surabaya, Indonesia, January, February and July are characterised by the lowest temperatures, recording an average high of 30.1°C (86.2°F).

How hot is it in Surabaya in January?

The high-temperature, in January, in Surabaya, is 30.1°C (86.2°F), while the low-temperature averages to 25.3°C (77.5°F). The average heat index (a.k.a. 'feels like', 'real feel'), which factors the actual air temperature with the relative humidity, in January is evaluated at 37°C (98.6°F).

What is the average humidity in January in Surabaya?

The average relative humidity in January in Surabaya is 78%.

How much does it rain in Surabaya in January?

In January, in Surabaya, the rain falls for 27 days. Throughout January, 172mm (6.77") of precipitation is accumulated.

What is the sea water temperature in January in Surabaya?

In January, the average sea temperature is 29.3°C (84.7°F). For swimming, diving, and other water activities, temperatures between 25°C (77°F) and 29°C (84.2°F) are perceived as very enjoyable and pleasurable for prolonged periods without feeling uncomfortable.

What is the average length of the day in January in Surabaya?

In Surabaya, Indonesia, the average day length in January is 12h and 29min.

When is the sunrise / sunset in January in Surabaya?

In January, on the first day of the month, sunrise is at 05:16 and sunset at 17:48. On the last day of the month, in Surabaya, sunrise is at 05:29 and sunset at 17:55 WIB.

What is the month with the least sunshine in Surabaya?

The month with the least sunshine is January, with an average of 8.1h of sunshine.

How long on average sun shines in January in Surabaya?

In January, the average sunshine duration in Surabaya, Indonesia, is 8.1h.

What are the months with the highest UV index in Surabaya?

The months with the highest UV index are January through December, with an average maximum UV index of 7.

When is the lowest UV index in Surabaya?

The months with the lowest UV index in Surabaya, Indonesia, are January through December, with an average maximum UV index of 7.

What is the UV index intensity in January in Surabaya?

In Surabaya, Indonesia, the average daily maximum UV index in January is 7. A UV Index value of 6 to 7 symbolizes a high health risk from exposure to Sun's UV rays.

Average temperature in January
Surabaya, Indonesia

Average temperature in January - Surabaya, Indonesia
  • Average high temperature in January: 30.1°C

The warmest month (with the highest average high temperature) is October (32.9°C).
The months with the lowest average high temperature are January, February and July (30.1°C).

  • Average low temperature in January: 25.3°C

The month with the highest average low temperature is November (26.5°C).
The coldest month (with the lowest average low temperature) is August (24.2°C).

Average pressure in January
Surabaya, Indonesia

Average pressure in January - Surabaya, Indonesia
  • Average pressure in January: 1009mbar

The month with the highest atmospheric pressure is August (1011.4mbar).
The month with the lowest atmospheric pressure is December (1008.7mbar).

Average wind speed in January
Surabaya, Indonesia

Average wind speed in January - Surabaya, Indonesia
  • Average wind speed in January: 9.6km/h

The windiest month (with the highest average wind speed) is August (9.9km/h).
The calmest month (with the lowest average wind speed) is April (6.3km/h).

Average humidity in January
Surabaya, Indonesia

Average humidity in January - Surabaya, Indonesia
  • Average humidity in January: 78%

The month with the highest relative humidity is February (79%).
The month with the lowest relative humidity is October (63%).

Average rainfall in January
Surabaya, Indonesia

Average rainfall in January - Surabaya, Indonesia
  • Average rainfall in January: 172mm

The wettest month (with the highest rainfall) is February (179mm).
The driest month (with the least rainfall) is August (4mm).

Average rainfall days in January
Surabaya, Indonesia

Average rainfall days in January - Surabaya, Indonesia
  • Average rainfall days in January: 27 days

The month with the highest number of rainy days is January (27 days).
The month with the least rainy days is August (3.7 days).

Average sea temperature in January
Surabaya, Indonesia

Average sea temperature in January - Surabaya, Indonesia
  • Average sea temperature in January: 29.3°C

The best month for swimming (with the highest average sea temperature) is December (30.2°C).
The coldest month (with the lowest average sea temperature) is August (27.8°C).

Average daylight in January /
Average sunshine in January
Surabaya, Indonesia

Average daylight in January / Average sunshine in January - Surabaya, Indonesia
  • Average daylight in January: 12h and 3min

The month with the longest days is December (Average daylight: 12h and 30min).
The month with the shortest days is June (Average daylight: 11h and 42min).

  • Average sunshine in January: 8h and 1min

The months with the most sunshine are August, September and October (Average sunshine: 9h and 54min).
The month with the least sunshine is January (Average sunshine: 8h and 6min).

Average sunshine days in January
Surabaya, Indonesia

Average sunshine days in January - Surabaya, Indonesia
  • Average sunshine days in January: 3.1 days

The month with the most sunshine days is August (26 days).
The month with the least sunshine days is February (2.8 days).

Average UV index in January
Surabaya, Indonesia

Average UV index in January - Surabaya, Indonesia
  • Average UV index in January: 7

The months with the highest UV index are January, February, March, April, May, June, July, August, September, October, November and December (UV index 7).
The months with the lowest UV index are January, February, March, April, May, June, July, August, September, October, November and December (UV index 7).

Average cloud cover in January
Surabaya, Indonesia

Average cloud cover in January - Surabaya, Indonesia
  • Average cloud cover in January: 44

The month with the most cloud cover is January (Cloud cover 44).
The month with the least cloud cover is August (Cloud cover 11).

Average visibility in January
Surabaya, Indonesia

Average visibility in January - Surabaya, Indonesia
  • Average visibility in January: 9km

The months with the highest visibility are March, April, May, June, July, August, September, October, November and December (10km).
The months with the lowest visibility are January and February (9km).

Surabaya, Indonesia

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