Last updated: August 21, 2025
In September, Hongkou, China experiences a dynamic weather pattern characterized by a maximum temperature reaching 35°C (94°F) and an average of 25°C (78°F), providing warm conditions for residents and visitors alike. The city faces a minimum temperature of 17°C (63°F), offering a comfortable evening respite. However, be prepared for significant rainfall, as 177 mm (7.0 in) of precipitation is recorded over 13 days, contributing to a high humidity level of 81%. This blend of warmth and moisture creates a vibrant atmosphere in Hongkou, ideal for summer-fall transitions but necessitating readiness for occasional downpours.
In September, Hongkou, China transitions into a milder climate as summer gives way to autumn. With minimum temperatures around 17°C (63°F) and average highs reaching 35°C (94°F), the month is characterized by warm days and pleasant evenings. This is a notable shift from the intense heat experienced in July and August, where temperatures peaked near 39°C (102°F). As the month progresses, the average temperature of 25°C (78°F) beckons outdoor activities and events, making it an ideal time to explore the vibrant streets and parks of Hongkou. The gradual decline in temperatures signals the approach of fall, inviting a more comfortable and enjoyable atmosphere for both residents and visitors alike.
In September, Hongkou experiences a significant shift in precipitation patterns, with rainfall totaling 177 mm (7.0 in) over 13 days. This marks a slight decrease from the heavy downpours of July and August, which collectively delivered some of the year's highest totals at 250 mm (9.8 in) and 167 mm (6.6 in), respectively. As summer transitions into autumn, September's rains often come in lighter bursts, but they're still essential for nourishing the landscape. The steady decline from June's peak of 201 mm (7.9 in) shows a gradual tapering off as the region prepares for the drier months ahead. Overall, September serves as a bridge, maintaining a vibrant green before the foliage shifts into the hues of fall.
In September, humidity levels in Hongkou, China begin to settle after a summer of elevated moisture, dropping to 81%. This marks a notable decline from the peak of 93% in July and 91% in August, as the region transitions from the sweltering summer months. Throughout the year, humidity steadily increases from 70% in January to a summer high, before gently tapering off in the fall. This trend highlights a pattern of high humidity during the warmer months, providing a refreshing respite as autumn approaches, while still remaining relatively comfortable compared to the humid highs seen earlier in the season.
In September, Hongkou, China, experiences an extreme UV Index of 11, indicative of the ongoing summer heat and intense sun exposure. With a burn time of just 10 minutes, it’s crucial for residents and visitors alike to take proper precautions—like wearing sunscreen and protective clothing—to avoid skin damage. This month continues the trend seen in the preceding summer months, where the UV Index reaches its peak, establishing a pattern that emphasizes the need for awareness during this time of the year. As autumn arrives, the UV Index is expected to drop in October, but for now, September stands as a reminder of the sun's power. For more detailed information, you can refer to the Hongkou UV Index.
UV Risk Categories
As September arrives in Hongkou, the city experiences a noteworthy decline from the sun-soaked heights of summer, with the month delivering 260 hours of sunshine. While this marks a significant reduction compared to the 318 hours basked in during August, it still reflects a generous abundance of light. The trend from the early months of the year showcases a gradual ascent in sunshine hours, peaking in the heat of summer before tapering off in fall. September serves as a gentle transition, marrying the lingering warmth of summer with the cooler whispers of autumn, inviting both residents and visitors alike to enjoy the vibrant cityscape under the softening sunshine.
As summer fades, September in Hongkou presents a refreshing shift in weather patterns, with a 44% chance of sunny days. This marks a notable increase from the oppressive heat of July and the variable skies of August. Although September's sunlit opportunities don't quite reach the heights of winter months like December, which enjoys a 64% chance, it does offer more potential for clear skies compared to the wetter summer months. The gradual rise from August's 34% reflects a trend toward more enjoyable weather, making September an appealing time for outdoor activities and exploration in Hongkou.
As September arrives in Hongkou, China, daylight begins to wane, offering 12 hours of sunlight—a gentle decline from the vibrant 14 hours of June. This transitional month marks a shift from the long, sun-filled days of summer, as daylight gradually decreases toward the autumn threshold. Following a summer peak, the daylight duration remains steady through August before dipping, hinting at the seasonal change ahead. This pattern illustrates the cyclical nature of light throughout the year, where September serves as a bridge, reminding residents of the approaching cooler months while still basking in the lingering warmth of summer.
September in Hongkou, China, brings a gentle breeze with an average wind speed of 3.6 m/s (8 mph), a slight increase from August's calmer days. As the warmth of summer transitions into the cooler embrace of autumn, this month reflects a consistent pattern of wind speeds ranging between 3.1 to 5.1 m/s throughout the year. Notably, July stands out with its peak wind speed of 5.1 m/s (11 mph), while the rest of the months hover around the 8 mph mark, creating a serene atmosphere. The winds, though modest, play a subtle role in shaping the vibrant autumn landscape, inviting reflections on the changing seasons and the dynamic energy of the city as it prepares for the cooler months ahead.
Weather in Hongkou varies notably across the year, with each month offering distinct climate conditions. This page compares September’s weather to other months in Hongkou, focusing on differences in temperature, rainfall, humidity, and UV levels.
September and January present quite contrasting weather patterns. In September, temperatures range from a mild 17°C (63°F) to a scorching 35°C (94°F), with an average of 25°C (78°F) and high humidity at 81%. This month also experiences significant rainfall, totaling 177 mm (7.0 in) over 13 days. Conversely, January brings much cooler temperatures, with a minimum of -8°C (19°F) and a maximum of 22°C (71°F), averaging just 6°C (44°F). Precipitation drops to 55 mm (2.2 in) across only 6 days, accompanied by lower humidity levels at 70%. For more detailed information about January weather, you can check Hongkou weather in January.
September and February present strikingly different weather patterns. In September, temperatures range from a minimum of 17°C (63°F) to a maximum of 35°C (94°F), with an average temperature of 25°C (78°F). This month is characterized by high humidity at 81% and considerable rainfall, totaling 177 mm (7.0 in) over 13 days. In contrast, February experiences much cooler conditions, with temperatures ranging from a low of -3°C (27°F) to a high of 24°C (76°F), averaging 7°C (45°F). Precipitation is significantly lower at 60 mm (2.4 in) over just 8 days, and humidity is comparatively less at 73%. For more insights, you can check Hongkou weather in February.
In September, the weather presents a warm and humid atmosphere, with average temperatures ranging from 17°C (63°F) to a high of 35°C (94°F) and substantial precipitation of 177 mm (7.0 in) over 13 days. This contrasts sharply with March, where temperatures are significantly cooler, ranging from a minimum of 2°C (37°F) to a maximum of 26°C (79°F), accompanied by a reduced precipitation of 83 mm (3.3 in) over 12 days. Despite both months sharing the same humidity level of 81%, the overall climate experience is quite different, with September feeling much more tropical compared to the crisp and mild conditions of March. For more details, you can check Hongkou weather in March.
September weather is notably warmer than April, with average temperatures reaching 25°C (78°F) compared to April's 16°C (61°F). The maximum temperatures in September can soar to 35°C (94°F), while in April, they peak at 31°C (87°F). Additionally, September experiences higher precipitation levels, averaging 177 mm (7.0 in) over 13 days, in contrast to April's 72 mm (2.8 in) over 9 days. Despite being the wetter month, April has a fresher feel with slightly lower humidity levels at 87%, compared to September's 81%. For a detailed look at the weather specifics in April, you can visit Hongkou weather in April.
In September, the weather tends to be warmer than in May, with average temperatures reaching 25°C (78°F) compared to May's average of 21°C (71°F). However, September experiences higher maximum temperatures, peaking at 35°C (94°F), while May matches this high of 34°C (94°F). Both months see a significant amount of precipitation, but September is notably wetter, with 177 mm (7.0 in) over 13 days, compared to May's 117 mm (4.6 in) over 10 days. Humidity levels are also higher in May at 87%, while September has a relative humidity of 81%. For a more detailed overview, you can check Hongkou weather in May.
In comparing the weather of September and June, we find that both months exhibit warm temperatures, but subtle differences exist. In September, the minimum temperature dips slightly to 17°C (63°F) while the average remains at 25°C (78°F), with a maximum reaching 35°C (94°F). In contrast, June starts at a higher minimum of 18°C (65°F) and can peak at 36°C (96°F). Precipitation levels are also notable; September experiences about 177 mm (7.0 in) over 13 days, while June sees more rain, totaling 201 mm (7.9 in) across 15 days. Additionally, the humidity is higher in June at 89% compared to 81% in September. For a detailed overview, you can check Hongkou weather in June.
When comparing the weather in September and July, notable differences emerge in temperature and precipitation patterns. September generally experiences milder temperatures with a minimum of 17°C (63°F) and an average of 25°C (78°F), while July is warmer, featuring a minimum of 20°C (69°F) and an average of 29°C (84°F). July also sees higher maximum temperatures, reaching up to 39°C (102°F) compared to September's peak of 35°C (94°F). In terms of precipitation, July is wetter, recording 250 mm (9.8 in) over 16 days, whereas September has 177 mm (7.0 in) spread across 13 days. Humidity levels are higher in July at 93%, contrasted with 81% in September. For more details, check out Hongkou weather in July.
In comparing the weather of September to August, we see a noticeable shift in temperature and conditions. September experiences a more moderate temperature range, with a minimum of 17°C (63°F) and an average of 25°C (78°F), compared to August's warmer minimum of 20°C (69°F) and an average of 29°C (85°F). The maximum temperatures also decline from August's peak of 38°C (100°F) to September's maximum of 35°C (94°F). While precipitation levels are similar, September has slightly more rainfall at 177 mm (7.0 in) over 13 days compared to August's 167 mm (6.6 in) over 15 days. Additionally, humidity decreases slightly in September, averaging at 81% versus August’s 91%. For more detailed information on August weather, you can visit Hongkou weather in August.
In September, the weather is characterized by warmer temperatures, with a minimum of 17°C (63°F) and an average high of 35°C (94°F), making it feel quite hot. This month also sees considerable rainfall, with 177 mm (7.0 in) accumulated over 13 days, and humidity levels around 81%. In contrast, October brings cooler temperatures, dropping to a minimum of 10°C (51°F) and averaging around 20°C (68°F), with a maximum of 31°C (89°F). The precipitation significantly decreases to 69 mm (2.7 in) over just 7 rainy days, and humidity remains relatively stable at 80%. For more detailed information, you can check out Hongkou weather in October.
September and November present stark contrasts in weather conditions. In September, temperatures range from a mild 17°C (63°F) at night to a sweltering 35°C (94°F) during the day, with an average of 25°C (78°F). The month is characterized by substantial rainfall, totaling 177 mm (7.0 in) over 13 days, along with high humidity levels of 81%. In contrast, November sees much cooler temperatures, with nighttime lows dropping to 2°C (37°F) and a comfortable daytime high of 27°C (81°F), averaging around 15°C (59°F). Precipitation is significantly reduced to 51 mm (2.0 in) across just 7 days, while humidity slightly rises to 82%. For more detailed insights, check out Hongkou weather in November.
September weather is characterized by warm temperatures, with averages around 25°C (78°F) and highs reaching up to 35°C (94°F), making it feel quite tropical. Additionally, this month sees considerable rainfall, with about 177 mm (7.0 in) over 13 days, resulting in a humidity level of 81%. In contrast, December brings a significant drop in temperatures, with averages around 8°C (47°F) and highs only reaching 20°C (69°F). Precipitation is much lower during this month, totaling 50 mm (2.0 in) over just 8 days, and the humidity remains relatively high at 77%. For more detailed information on December weather, you can visit Hongkou weather in December.
As September unfolds in Hongkou, the sweltering heat of summer begins to wane, but the average temperature still hovers around a pleasant 25°C (78°F). Unlike the brief summer peaks, where temperatures can soar to a maximum of 35°C (94°F), September offers a welcome reprieve, balancing warmth with the first whispers of autumn. However, expect an increased chance of rain, with 177 mm of precipitation spread over 13 days, contributing to a relatively high humidity level of 81%. This makes September a transitional month, blending summer's lingering warmth with the cool, invigorating breezes of fall. For a deeper dive into what to expect from Hongkou's climate throughout the year, explore Hongkou Climate.