September Weather in Osaka, Japan

Last updated: August 21, 2025

In September, Osaka experiences a blend of warmth and humidity, with maximum temperatures soaring to a sizzling 37°C (99°F) and an average resting comfortably at 25°C (78°F). The city also witnesses a notable minimum temperature of 15°C (59°F), providing a refreshing contrast. However, this period is marked by significant precipitation, accumulating 169 mm (6.7 in) over roughly 15 days, and the humidity levels hover around a muggy 87%, contributing to a tropical atmosphere. Visitors can expect vibrant landscapes yet should prepare for wet weather interspersed with sultry warmth.

September Temperature in Osaka

As September arrives in Osaka, Japan, the city experiences a warm transition from summer to autumn. The minimum temperature settles at a comfortable 15°C (59°F), while the average climbs to a pleasant 25°C (78°F), making it an ideal time for outdoor activities and exploring the vibrant city. Daytime temperatures can soar to a high of 37°C (99°F) as remnants of summer linger, but the evenings tend to cool down, inviting locals and visitors alike to enjoy the fresher air. This month also marks a sweet spot in the weather, offering a delightful blend of warmth and cooling breezes, creating the perfect backdrop for enjoying Osaka's famous street food and picturesque parks. As the month progresses, the gradual drop in temperatures signals the oncoming fall, inviting a picturesque change in the landscape and a welcome reprieve from the soaring summer heat.

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

The chart illustrates September temperature patterns in Osaka, showcasing daily minimum, maximum, and average temperatures. It highlights the typical range of temperatures throughout the month, providing insights into weather trends. In Osaka, September typically has an average temperature of {2}°C ({3}°F), with highs reaching up to {4}°C ({5}°F) and lows dropping to around {6}°C ({7}°F).
JanFebMarAprMayJunJulAugSepOctNovDec424351596874828577675647
Data source: Temperature data for Osaka generated using information from the Copernicus Climate Change Service.
Choose your preferred temperature unit
The average of daily temperatures (24 hours) calculated across all days in the month.

September Precipitation in Osaka

In September, Osaka experiences a significant shift in precipitation as the summer months wane. With 169 mm (6.7 in) of rainfall over 15 days, it marks a transition from the heavy downpours of July and August to a more moderate, yet consistent, pattern. This month stands out with a notable amount of rain that supports the lush landscapes often seen after the peak of the rainy season. Interestingly, September's precipitation is less than July's torrential 282 mm (11.1 in) but remains substantial enough to highlight the late-summer climate. As the city gradually moves towards October, where rainfall increases again to 230 mm (9.0 in), residents can expect a lush vibrant environment nourished by these late-summer showers. This trend not only defines September's role in the seasonal cycle but also underscores Osaka's diverse climate, characterized by both the intensity of summer storms and the refreshing rejuvenation of autumn rains.

September Precipitation Trends in Osaka

The chart displays monthly precipitation patterns in Osaka, 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 Osaka, September typically receives around {2} mm ({3} inches) of precipitation spread over approximately {4} days.
JanFebMarAprMayJunJulAugSepOctNovDec46601091351501472821831692304457
Data source: Precipitation data for September generated using information from the Copernicus Climate Change Service.
Choose your preferred precipitation unit

September Humidity in Osaka

In September, Osaka experiences a notable drop in humidity compared to the sweltering summer months, settling at 87%. This residual warmth lingers from July and August, where humidity peaks at an intense 93% and 91%, respectively. As the city transitions into autumn, September’s humidity represents a slight but significant reduction, hinting at the seasonal change ahead. Following this month, the humidity tends to decrease further in October and November, creating a more comfortable atmosphere as the region steps into fall. This gradual shift showcases Osaka's distinct seasonal patterns, where the balmy summer gradually yields to the crispness of autumn.

September Average Humidity in Osaka

This chart illustrates the average monthly humidity levels in Osaka, 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 Osaka is approximately {2}%, offering insight into how humid the weather typically is during this month.
JanFebMarAprMayJunJulAugSepOctNovDec82%79%74%76%83%87%93%91%87%85%83%83%
Data source: Humidity data for September generated using information from the Copernicus Climate Change Service.

September UV Index in Osaka

In September, Osaka experiences a very high UV Index of 10, marking a slight decrease from the extreme levels seen during the peak summer months. With a burn time of 15 minutes, individuals are advised to take precautions to protect their skin from harmful UV radiation. This trend reveals that while the intense summer sun begins to wane, caution is still necessary as autumn approaches. The transition from extreme UV levels in July and August to this very high rating underscores the need for awareness, especially for outdoor activities during this month. For more detailed information on UV levels throughout the year, check out the Osaka UV Index.

Maximum UV Index Levels in Osaka for September

The chart shows the monthly maximum UV Index (UVI) for Osaka 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 Osaka typically reaches {2}, which falls under the {3} exposure category.
JanFebMarAprMayJunJulAugSepOctNovDec468111111121110753
Data source: Osaka 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.

September Sunshine in Osaka

As summer gracefully transitions into autumn, September in Osaka continues to bask in the warmth of the sun, boasting an impressive 242 hours of sunshine. This marks a slight dip from the sun-soaked peak of August, which dazzled with 305 hours but remains a vibrant month in the annual cycle. Notably, sunshine hours show a remarkable upward trend starting from the chill of January, where daylight barely reaches 185 hours, gradually climbing to the sunny heights of late summer. Following September, the days begin to shorten, with October and November presenting slightly diminished sunshine, yet the lingering brightness of early fall is a charming reminder of summer's embrace, making Osaka a delightful destination for those seeking daylight and warmth.

Monthly Sunshine Duration in Osaka: September Highlighted

The September sunshine duration represents the total number of hours Osaka experiences direct sunlight during the month of September, excluding cloudy or obstructed periods. This chart compares the sunshine duration of September with the other months of the year.
JanFebMarAprMayJunJulAugSepOctNovDec185h229h265h279h291h268h258h305h242h237h236h221h
Data source: Osaka September Sunshine duration data generated using information from the Copernicus Climate Change Service.

Chance of Sun in Osaka During September

In Osaka, Japan, September sees a 30% chance of sunny weather, making it one of the more unpredictable months for sunshine as summer transitions to autumn. This figure places September among the lower probabilities for sunlight, following the very humid and overcast months of June and August, which recorded even lower chances at 24% and 28%, respectively. Interestingly, the likelihood improves in the following months, with October leaping to 53%, suggesting a charming return to clearer skies. Thus, while September may not shine as brightly as some other months, it remains a noteworthy time for those seeking to embrace the cusp of fall in this vibrant city.

Percentage of Sunny Days in September in Osaka

The chart illustrates the percentage of sunny days in Osaka throughout the year, with September highlighted. It highlights the variation in sunshine across each month and provides an overview of the typical frequency of sunny days, offering insights into how often Osaka experiences clear skies throughout the year.
JanFebMarAprMayJunJulAugSepOctNovDec49%52%41%45%29%24%32%28%30%53%52%57%
Data source: Osaka September chance of sun data, generated using information from the Copernicus Climate Change Service.

Daylight Hours in Osaka in September

As summer transitions to fall in Osaka, September offers a delightful balance with 12 hours of daylight. This month marks a gradual decline from the lengthy summer days of July and June, which boast 14 hours of sunlight, to the more subdued illumination of October at 11 hours. The shift towards autumn is evident as the daylight hours decrease, reflecting the region's natural rhythm. Visitors and locals alike can enjoy the warm hues of early autumn while still benefitting from ample daylight, making September a perfect time to explore Osaka's vibrant streets and stunning landscapes. This subtle shift in daylight sets the stage for the cozy charm of the coming months.

Average Daylight Hours in Osaka for September

The chart illustrates the variation in daylight duration in Osaka throughout the year, with September highlighted. It shows the monthly changes in daylight hours, calculated by summing the hours between sunrise and sunset.
JanFebMarAprMayJunJulAugSepOctNovDec10h 5m10h 54m11h 58m13h 3m13h 58m14h 25m14h 12m13h 24m12h 21m11h 16m10h 20m9h 51m
Data source: Osaka daylight hours, calculated by summing the hours between sunrise and sunset for each day.

September Winds in Osaka

As September sweeps into Osaka, the city experiences a gentle sigh of wind with an average speed of 2.2 m/s (5 mph). This slight breeze is characteristic of the early autumn transition, reflecting a notable decrease from the summer months. Compared to June and July, where wind speeds dipped to their lowest at 1.8 m/s (4 mph) and 2.0 m/s (4 mph), September maintains a refreshing, albeit mild, airflow that heralds the approach of cooler weather. This month acts as a serene bridge between the sweltering summer and the crisp autumn days, inviting residents and visitors alike to enjoy the soft caress of the wind while basking in Osaka's beautiful parks and gardens. As the month progresses into October, the wind speed remains stable, suggesting a continued embrace of the restful pace of early fall.

Average September Wind Speed in Osaka

The chart displays monthly wind speed patterns in Osaka, with values for each month shown alongside September's data, which is highlighted for easy comparison. It illustrates the average wind speed, offering insights into how September's wind conditions compare to the rest of the year.
JanFebMarAprMayJunJulAugSepOctNovDec2.93.12.72.72.71.82.02.42.2 m/s2.22.32.8
Data source: Osaka September wind data, generated using information from the Copernicus Climate Change Service.

How September Weather in Osaka Compares to Other Months

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

September and January present contrasting weather conditions. In September, temperatures range from a mild 15°C (59°F) to a sweltering maximum of 37°C (99°F), with an average of 25°C (78°F). This month sees significant rainfall, with 169 mm (6.7 in) spread over 15 days, and humidity levels peaking at 87%. In stark contrast, January experiences much cooler temperatures, ranging from a minimum of -3°C (26°F) to a maximum of 18°C (64°F), leading to an average of only 6°C (42°F). The precipitation in January is considerably lower at 46 mm (1.8 in) over just 6 days, and humidity is slightly lower at 82%. For more details about the weather, you can check Osaka weather in January.

September and February present starkly contrasting weather conditions. In September, temperatures can range from a minimum of 15°C (59°F) to a scorching maximum of 37°C (99°F), with an average temperature of 25°C (78°F). This month also experiences significant precipitation, with about 169 mm (6.7 in) spread over 15 rainy days and a humidity level reaching 87%. In contrast, February is much cooler, featuring a minimum temperature of -3°C (26°F) and a maximum of 20°C (68°F), with an average of only 6°C (43°F). The month sees considerably less rainfall, measuring just 60 mm (2.3 in) over 6 days, and a lower humidity of 79%. For a more detailed look at February's weather in Osaka, you can visit Osaka weather in February.

In September, the weather is characterized by warm temperatures, with daily averages around 25°C (78°F) and maximums soaring up to 37°C (99°F), accompanied by high humidity at 87%. Rainfall is also quite significant, with about 169 mm (6.7 in) occurring over approximately 15 days. In stark contrast, March presents a cooler climate, with temperatures ranging from a minimum of -1°C (31°F) to a maximum of 23°C (73°F) and an average of 10°C (51°F). Precipitation is lower at 109 mm (4.3 in) over 11 days, and the humidity drops to 74%. For more details on the weather specific to March, you can refer to Osaka weather in March.

September and April present contrasting weather patterns. In September, temperatures range from a minimum of 15°C (59°F) to a scorching maximum of 37°C (99°F), with an average of 25°C (78°F). The month is notably humid, with a high humidity level of 87% and considerable precipitation at 169 mm (6.7 in) spread over 15 days. In contrast, April boasts milder temperatures, with a minimum of 3°C (37°F), an average of 15°C (59°F), and a maximum of 26°C (79°F). This month experiences less rainfall, totaling 135 mm (5.3 in) over 10 days, and lower humidity at 76%. For more specific details about April weather, refer to Osaka weather in April.

September and May exhibit distinct weather patterns that reflect the transition between seasons. In September, temperatures range from a minimum of 15°C (59°F) to a maximum of 37°C (99°F), with an average of 25°C (78°F). The month experiences considerable humidity at 87% and substantial rainfall, totaling 169 mm (6.7 in) over 15 days. In contrast, May features a milder climate, with temperatures ranging between 8°C (47°F) and 31°C (88°F), averaging around 20°C (69°F). It experiences less humidity at 83% and slightly lower precipitation totals of 150 mm (5.9 in) over 10 days. Overall, September's weather is generally hotter and wetter compared to May. For more detailed insights, you can check Osaka weather in May.

In comparing the weather of September and June, both months experience relatively warm temperatures, but September tends to be hotter, with average daily highs reaching up to 37°C (99°F) compared to June’s maximum of 32°C (89°F). The minimum temperatures are also slightly higher in September, with lows around 15°C (59°F) versus 14°C (58°F) in June. Additionally, September sees more rainfall, accumulating 169 mm (6.7 in) over 15 days, while June receives 147 mm (5.8 in) across 12 days. Despite this, both months maintain a high humidity level at 87%, contributing to a sultry atmosphere. For a more detailed look at June weather, you can visit Osaka weather in June.

In comparing the weather of September and July, both months experience high temperatures, with September's averages ranging from a cool 15°C (59°F) at night to a warm 37°C (99°F) during the day, while July sees slightly warmer nighttime temperatures starting at 20°C (69°F) and averaging 28°C (82°F). Precipitation levels are notably higher in July, with 282 mm (11.1 in) falling over 18 days, contrasted with September's 169 mm (6.7 in) over 15 days. Humidity also plays a significant role, remaining higher in July at 93% compared to September's 87%. For more detailed insights on July weather, you can refer to Osaka weather in July.

In comparison to August, September experiences a notable drop in average temperatures, with minimums around 15°C (59°F) and a maximum of 37°C (99°F), compared to August's milder range of 19°C (66°F) to 38°C (101°F). The average temperature in September is 25°C (78°F), while August boasts a warmer average of 29°C (85°F). Moreover, September sees a slight increase in precipitation, with 169 mm (6.7 in) spread over 15 days, compared to August’s 183 mm (7.2 in) over 12 days. Humidity levels also remain high in September at 87%, though slightly lower than August’s 91%. For more insights, check out Osaka weather in August.

September typically offers warmer temperatures than October, with a minimum of 15°C (59°F) and an average of 25°C (78°F), peaking at a sweltering maximum of 37°C (99°F). However, it also sees significant rainfall, accumulating 169 mm (6.7 in) over approximately 15 days, and high humidity levels of 87%. In contrast, October experiences a notable drop in temperatures, with lows of 8°C (46°F) and an average of 20°C (67°F), making it more comfortable overall. Despite the cooler weather, October is wetter, with 230 mm (9.0 in) of precipitation over 12 days, and humidity remains slightly lower at 85%. For a detailed look at what to expect, check out Osaka weather in October.

September weather is characterized by warmth and humidity, with average temperatures around 25°C (78°F) and highs reaching up to 37°C (99°F). Rain is fairly common, with 169 mm (6.7 in) of precipitation spread across 15 days, resulting in a humid atmosphere at 87%. In contrast, November brings a significant drop in temperatures, with averages falling to 13°C (56°F) and nighttime lows dipping to 2°C (35°F). The month also experiences much less rain, totaling only 44 mm (1.7 in) over 6 days and maintaining a slightly lower humidity of 83%. For more insight into the weather conditions during this month, check out Osaka weather in November.

In comparison, September features significantly warmer temperatures, ranging from a minimum of 15°C (59°F) to a maximum of 37°C (99°F), with an average of 25°C (78°F). The month experiences substantial rainfall, totaling 169 mm (6.7 in) over approximately 15 days, coupled with high humidity levels of 87%. In contrast, December ushers in much cooler weather, with temperatures dropping to a minimum of -1°C (30°F) and an average of just 8°C (47°F), peaking at a maximum of 22°C (71°F). Precipitation is notably lower at 57 mm (2.2 in) over 6 days, with slightly lower humidity at 83%. For more details, you can check Osaka weather in December.

Compare Osaka's Climate with Cities Worldwide

Conclusion: What to Expect From September Weather in Osaka

As summer gives way to fall, September in Osaka presents a striking transition in weather. With high humidity levels hovering around 87%, the air feels thick, yet the average temperature remains milder compared to the scorching summer months. While occasional heatwaves can push the mercury to a maximum of 37°C, the cooler evenings, featuring temperatures dipping to a refreshing 15°C, offer a welcome reprieve. However, prepare for the wet conditions as September sees an average of 169 mm of rainfall over 15 days, making it one of the more humid months of the year. This unique blend of warmth and precipitation makes September a month of contrasts, setting the stage for the forthcoming autumn season. For more insights into the yearly weather patterns, visit Osaka Climate.