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September Weather in Surabaya, Indonesia

Last updated: August 23, 2025

In September, the average temperature in Surabaya, Indonesia is a comfortable 27°C (81°F), with daily temperatures ranging from a minimum of 21°C (70°F) to a maximum of 33°C (92°F). Expect 97 mm (3.8 in) of precipitation spread over 15 days, contributing to an average humidity of 74%.

September Temperature in Surabaya

In September in Surabaya, the average temperature is 27°C (81°F). Maximums can reach 33°C (92°F), and minimums can drop as low as 21°C (70°F). This makes it an ideal destination for travelers looking for warm and pleasant weather.

September Weather in Surabaya: Daily Temperature Highs, Lows, and Averages

The chart illustrates September temperature patterns in Surabaya, showcasing daily minimum, maximum, and average temperatures. It highlights the typical range of temperatures throughout the month, providing insights into weather trends. In Surabaya, September typically has an average temperature of 27°C (81°F), with highs reaching up to 33°C (92°F) and lows dropping to around 21°C (70°F).
JanFebMarAprMayJunJulAugSepOctNovDec818181828281808081828281
Data source: Temperature data for Surabaya generated using information from the Copernicus Climate Change Service.
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The average of daily temperatures (24 hours) calculated across all days in the month.

September Precipitation in Surabaya

In Surabaya in September, the total precipitation amount is 97 mm (3.8 in) spread over 15 days.

September Precipitation Trends in Surabaya

The chart displays monthly precipitation patterns in Surabaya, with values for each month alongside September’s data, which is highlighted for easy comparison. It shows the amount of precipitation, providing insights into how September’s conditions compare to those of other months. In Surabaya, September typically receives around 97 mm (3.8 inches) of precipitation spread over approximately 15 days.
JanFebMarAprMayJunJulAugSepOctNovDec2573254183182421981077797118250340
Data source: Precipitation data for September generated using information from the Copernicus Climate Change Service.
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September Humidity in Surabaya

In Surabaya in September humidity is 74%. With an average temperature of 27°C (81°F), this humidity feels like a warm, enveloping blanket, making traveling feel both sticky and draining, yet the heat invites you to seek out refreshing dips in pools or shady spots to relax.

September Average Humidity in Surabaya

This chart illustrates the average monthly humidity levels in Surabaya, with September’s data highlighted for easy comparison. It shows the fluctuation in humidity throughout the year, helping you understand how conditions vary by season. In September, average humidity in Surabaya is approximately 74%, offering insight into how humid the weather typically is during this month.
JanFebMarAprMayJunJulAugSepOctNovDec85%86%84%82%80%80%80%78%74%76%78%80%
Data source: Humidity data for September generated using information from the Copernicus Climate Change Service.

September UV Index in Surabaya

In Surabaya in September, the maximum UV index is 14, which corresponds to an extreme Exposure Category. The time to burn is just 10 minutes, so it's crucial to take precautions. For the detailed hourly UV index in Surabaya, you can check here.

Maximum UV Index Levels in Surabaya for September

The chart shows the monthly maximum UV Index (UVI) for Surabaya in September, representing the highest UV radiation level. The UVI measures the intensity of ultraviolet radiation from the sun, indicating the potential risk of sunburn and UV-related health issues. In September, the maximum UV index in Surabaya typically reaches 14, which falls under the extreme exposure category.
JanFebMarAprMayJunJulAugSepOctNovDec151516151311121314151514
Data source: Surabaya September UVI data generated using information from the Copernicus Climate Change Service.

UV Risk Categories

  •  Extreme (11+): Avoid the sun, stay in shade.
  •  Very High (8-10): Limit sun exposure.
  •  High (6-7): Use SPF 30+ and protective clothing.
  •  Moderate (3-5): Midday shade recommended.
  •  Low (0-2): No protection needed.

How September Weather in Surabaya Compares to Other Months

Weather in Surabaya varies notably across the year, with each month offering distinct climate conditions. This page compares September’s weather to other months in Surabaya, focusing on differences in temperature, rainfall, humidity, and UV levels.

This table compares monthly weather conditions in Surabaya, showing how September’s temperature, precipitation, humidity, and UV index levels differ from those of other months.
 TemperaturePrecipitationHumidityUV
January Weather27°C (81°F)257 mm (10.1 inches)85%extreme
February Weather27°C (81°F)325 mm (12.8 inches)86%extreme
March Weather27°C (81°F)418 mm (16.4 inches)84%extreme
April Weather28°C (82°F)318 mm (12.5 inches)82%extreme
May Weather28°C (82°F)242 mm (9.5 inches)80%extreme
June Weather27°C (81°F)198 mm (7.8 inches)80%extreme
July Weather27°C (80°F)107 mm (4.2 inches)80%extreme
August Weather27°C (80°F)77 mm (3.0 inches)78%extreme
September Weather27°C (81°F)97 mm (3.8 inches)74%extreme
October Weather28°C (82°F)118 mm (4.6 inches)76%extreme
November Weather28°C (82°F)250 mm (9.8 inches)78%extreme
December Weather27°C (81°F)340 mm (13.4 inches)80%extreme

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