Last updated: August 21, 2025
Experience the vibrant atmosphere of Surabaya, Indonesia in September, where the weather presents a delightful mix of warmth and humidity. With maximum temperatures reaching up to 36°C (96°F) and an average of 29°C (84°F), the days are ripe for outdoor adventures. Evenings bring a refreshing contrast, with lows around 23°C (75°F). While the city enjoys an average precipitation of 21 mm (0.8 in) over 4 rainy days, the humidity sits comfortably at 72%, creating a lush and inviting environment. Enjoy the balance of sun and occasional showers that characterize this tropical gem, perfect for exploring its rich culture and vibrant landscapes.
In September, Surabaya experiences warm temperatures that signal the transition into the hotter months of the year. The minimum temperature hovers around 23°C (75°F), providing a pleasant start to the day, while the average rises to 29°C (84°F), reflecting the city's tropical climate. The heat peaks with a maximum of 36°C (96°F), making it one of the hottest months in Surabaya. This trend of increasing warmth is consistent as the region approaches October, indicating a steady climb in temperatures throughout the late months of the year. With fairly high humidity levels accompanying the heat, it's the perfect time for visitors to enjoy the vibrancy of this bustling city while staying hydrated.
September in Surabaya, Indonesia, marks a transitional period as the dry season comes to a close, bringing a slight uptick in precipitation. With 21 mm (0.8 in) of rainfall spread over just 4 days, this month is relatively wet compared to the preceding two months, which saw minimal rain. The gradual increase in precipitation signals the onset of the rainy season, setting the stage for a significant rise in rainfall from October onward. This shift indicates a retreat from the dry spell of mid-year, as residents can expect more moisture-laden days ahead, with November and December anticipating some of the highest rainfall totals of the year.
In September, Surabaya experiences a relatively lower humidity level of 72%, marking a notable decrease from the more humid months earlier in the year. Following a trend of gradually reducing humidity from a high of 85% in February, the city dips to its lowest point of the year this month. The humidity steadily declines from August's 74%, signaling the onset of a drier season. This transition not only makes September a more comfortable month for residents and visitors alike but also hints at the approaching end of Surabaya’s tropical humidity peak as the weather begins to shift towards the tail end of the year.
In September, Surabaya, Indonesia, experiences a UV Index of 14, maintaining its position in the extreme exposure category with a consistent burn time of just 10 minutes. This trend reflects the region's ongoing pattern of high UV radiation year-round, particularly from January through August, where indices ranged from 12 to 15. Notably, while June and July saw a slight dip to a very high level of 10 and 11 respectively, September's UV intensity reaffirms the importance of sun safety precautions this time of year. With scorching UV levels persisting, it's crucial to stay informed about the local UV Index and protect your skin when enjoying the outdoors. For more insights, visit Surabaya UV Index.
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As September rolls into Surabaya, Indonesia, the city basks in 306 hours of sunshine, making it one of the sunniest months of the year. This marks a slight dip from the previous month, August, which boasts a remarkable 315 hours of sunlight. However, September maintains a stellar streak, following the summer peak of 311 hours in July. The sun-soaked days of this vibrant city highlight a trend of consistently high sunshine hours, particularly in mid and late year, where residents and visitors alike can savor the warm glow. With such abundance of sunlight, Surabaya remains a dazzling destination, inviting outdoor adventures and sunlit explorations well into the fall.
In September, Surabaya experiences a 33% chance of sunny weather, signaling a shift from the peak of the dry season. As the months progress from July, which boasts a 54% likelihood of sunshine, to August's 52%, September's sunshine potential sees a notable decrease. However, this drop is not as drastic as the transitions into October and November, where chances fall to 25% and a mere 5%, respectively. This trend indicates that while September marks a slight retreat from the summer sun, the opportunities for enjoying clear skies remain relatively favorable compared to the wetter months ahead. As such, September presents a sweet spot for those looking to bask in the lingering warmth before the rainy season begins.
In Surabaya, Indonesia, the daylight duration exhibits a fascinating consistency throughout the year. From January to March, the city enjoys a steady 12 hours of daylight, creating a perfect backdrop for vibrant activities. As the months transition into April through August, the days shorten slightly to 11 hours, a reflection of the changing seasons and cooler periods. However, come September, sunlight reasserts its dominance, bringing back 12 hours of brilliant daylight, which continues through October, November, and into December. This rhythmic cycle of daylight not only shapes daily life but also highlights Surabaya's tropical climate, where the sun remains a steadfast companion throughout the year.
In September, the winds in Surabaya, Indonesia greet the city with a gentle yet refreshing breeze, averaging 2.1 m/s (5 mph). This slight uptick from the previous month's 2.3 m/s signals a transition towards the milder winds of the coming months, as September sits squarely between the breezy peaks of August and the calmer currents of October, which drops to 1.5 m/s. Throughout the year, wind speeds in Surabaya typically show a trend of stability, with the later months generally experiencing lighter breezes. However, September holds a charming balance, maintaining enough airflow to keep the atmosphere lively, hinting at the seasonal shifts on the horizon while echoing the dynamic climate of this vibrant coastal city.
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.
When comparing the weather in September and January, September tends to be warmer on average with temperatures ranging from a minimum of 23°C (75°F) to a maximum of 36°C (96°F). This month experiences relatively low precipitation, with only about 21 mm (0.8 in) over just four days and humidity levels around 72%. In contrast, January is slightly cooler, with a minimum temperature of 25°C (77°F) and a maximum of 34°C (94°F). However, it is much wetter, receiving approximately 253 mm (10.0 in) of rain over 25 days and higher humidity at 81%. For more detailed information about January weather in Surabaya, you can visit Surabaya weather in January.
September and February present distinctly different weather conditions. In September, temperatures range from a minimum of 23°C (75°F) to a maximum of 36°C (96°F), with an average of 29°C (84°F). The month experiences relatively low precipitation, totaling just 21 mm (0.8 in) over about 4 days, accompanied by a humidity level of 72%. In contrast, February is warmer at the lower end, with a minimum temperature of 24°C (76°F), but features a cooler maximum of 33°C (92°F) and a slightly lower average of 28°C (82°F). However, February is significantly wetter, receiving 290 mm (11.4 in) of rainfall over 27 days, coupled with higher humidity at 85%. For a more detailed look at February's weather, visit Surabaya weather in February.
In September, the weather is typically warm, with temperatures ranging from a minimum of 23°C (75°F) to a maximum of 36°C (96°F), and an average of 29°C (84°F). This month sees relatively low precipitation, with only 21 mm (0.8 in) over about 4 days, and humidity levels around 72%. In contrast, March experiences slightly higher temperatures, with a minimum of 24°C (76°F), an average of 28°C (83°F), and a maximum of 33°C (92°F). However, March is significantly wetter, receiving 320 mm (12.6 in) of rain over 29 days, accompanied by a higher humidity rate of 83%. For more details on March's weather conditions, visit Surabaya weather in March.
September and April exhibit distinct weather patterns. In September, temperatures range from a minimum of 23°C (75°F) to a maximum of 36°C (96°F), with an average of 29°C (84°F). The month sees relatively low precipitation of 21 mm (0.8 in) over just 4 days, accompanied by humidity levels around 72%. In contrast, April experiences slightly warmer nights with a minimum temperature of 25°C (77°F) and a maximum of 34°C (93°F). The average temperature remains the same at 29°C (84°F), but the month is much wetter, receiving 175 mm (6.9 in) of rain across 24 days and higher humidity at 80%. For a more detailed look at April's climate specifics, visit Surabaya weather in April.
September and May both boast warm temperatures, but they exhibit distinct differences in weather patterns. September typically experiences minimum temperatures of 23°C (75°F) and maximums of 36°C (96°F), with an average of 29°C (84°F). In comparison, May shows a slightly higher minimum temperature of 24°C (76°F) and a lower maximum of 34°C (93°F), while maintaining a comparable average of 29°C (85°F). However, May is notably wetter, with 69 mm (2.7 in) of precipitation over 12 days, in contrast to September's much drier conditions, which see only 21 mm (0.8 in) of rain over 4 days. Additionally, May's humidity level is slightly higher at 81%, compared to September's 72%. For more details on May weather in Surabaya, you can check out Surabaya weather in May.
In comparing the weather of September and June, both months share a similar minimum and average temperature, with September seeing a slightly higher maximum temperature of 36°C (96°F) compared to June's 34°C (93°F). However, September is generally drier, receiving only 21 mm (0.8 in) of precipitation over four days, whereas June experiences more rain, with 51 mm (2.0 in) over ten days. Additionally, September's humidity is slightly lower at 72%, while June's humidity is at a higher 80%. For a detailed look at June's weather patterns, you can refer to Surabaya weather in June.
In comparing the weather of September and July, September tends to be slightly warmer, with average temperatures reaching 29°C (84°F) compared to July's 28°C (83°F). The maximum temperature in September can reach up to 36°C (96°F), making it more heat-intensive than July, where the maximum is 33°C (92°F). Additionally, September experiences more precipitation, totaling 21 mm (0.8 in) over about four days, whereas July receives less at 13 mm (0.5 in) across just two days. Humidity levels are somewhat lower in September at 72%, compared to July's 78%, providing a marginally more comfortable atmosphere. For more detailed information on July's climate, you can visit this link: Surabaya weather in July.
In comparing the weather between September and August, September tends to be slightly warmer, with average temperatures reaching up to 29°C (84°F) compared to August's average of 28°C (83°F). September also features higher maximum temperatures, soaring to 36°C (96°F), while August's peak is more moderate at 33°C (92°F). Additionally, September experiences notable increases in precipitation, with 21 mm (0.8 in) falling over four days, whereas August sees only 8 mm (0.3 in) over just two days. Humidity levels are fairly similar, with September at 72% and August at 74%. For more detailed information, check out Surabaya weather in August.
In comparing the weather between September and October, September tends to be slightly hotter with an average temperature of 29°C (84°F) and a maximum of 36°C (96°F), while October shows a minor increase in average temperature at 30°C (86°F), but the maximum dips to 35°C (96°F). One significant difference is the increase in precipitation during October, which sees 80 mm (3.1 in) of rain over 14 days, compared to only 21 mm (0.8 in) over 4 days in September. Humidity remains consistent at 72% for both months, creating a humid atmosphere regardless of the season. For more detailed information, you can check Surabaya weather in October.
September and November in Surabaya present a striking contrast in weather patterns. While both months share a warm average temperature of around 29°C (84°F), September experiences slightly lower nightly temperatures and less humidity compared to November. In September, the weather is relatively dry with only 21 mm of precipitation over four days, making it ideal for outdoor activities. However, November sees a significant increase in rain, with 208 mm falling over 26 days, leading to a more humid environment at 73%. This shift emphasizes the transition into the wet season, making November far wetter and more challenging for those unaccustomed to the higher moisture levels. For a deeper look into what to expect during this month, visit Surabaya weather in November.
September and December in Surabaya showcase distinct weather patterns. In September, temperatures range from a minimum of 23°C (75°F) to a maximum of 36°C (96°F), with an average of 29°C (84°F), and relatively low precipitation of 21 mm (0.8 in) across just 4 days. In contrast, December experiences slightly warmer nights with minimum temperatures of 24°C (76°F) and average temperatures of 28°C (83°F), but sees a significant increase in rainfall, totaling 302 mm (11.9 in) over 29 days. Furthermore, humidity remains high in both months, with September at 72% and December at 75%. For more detailed insights into December's climate, visit Surabaya weather in December.
As September unfolds in Surabaya, the city experiences a warm embrace with temperatures typically hovering around 29°C (84°F), making it a comfortable month compared to the sweltering highs of the preceding summer. With only 21 mm of rainfall spread over just four days, the precipitation is relatively low, allowing for longer stretches of sunshine to brighten the atmosphere. The humidity remains at a manageable 72%, striking a balance that feels inviting rather than stifling. In essence, September transitions Surabaya into a more temperate phase, serving as a refreshing pause before the onset of more intense weather patterns. For further insights into the dynamic weather throughout the year, check out Surabaya Climate.