Last updated: August 21, 2025
September in Hainan, China, brings a warm climate characterized by a maximum temperature of 28°C (83°F), balanced by a cooler average of 15°C (59°F) and a minimum dipping to 0°C (33°F). The month witnesses 103 mm (4.1 in) of precipitation spread over 9 days, creating a humid atmosphere with an average humidity level of 85%. Embrace the tropical feel of Hainan as the rain nourishes its lush landscapes, making it an ideal time for both relaxation and exploration.
In September, Hainan, China begins to transition into milder temperatures, showcasing a blend of comfortable warmth and cooling breezes. The minimum temperature hovers around 0°C (33°F), while average highs reach a pleasant 28°C (83°F), making it an ideal month for outdoor activities. With averages around 15°C (59°F), the weather is significantly warmer than the chilly depths of winter earlier in the year, yet not as sweltering as the peak summer months. As the island’s tropical climate shifts towards autumn, visitors can enjoy the sunny days, fresh sea breezes, and vibrant landscapes that make Hainan a captivating destination. This month effectively bridges the gap between the lingering warmth of summer and the cooling embrace of fall, inviting both adventurers and relaxation seekers alike.
September in Hainan, China, sees a significant dip in precipitation compared to the preceding months, with an average rainfall of 103 mm (4.1 in) over 9 days. This month typically marks the transition from Hainan's peak rainy season, which reaches its height in July and August, bringing a stunning 175 mm (6.9 in) and 183 mm (7.2 in), respectively. The rainfall begins to taper off sharply in October, where it drops to 22 mm (0.9 in), setting a clear trend of diminishing precipitation as the region heads into the drier months. Despite September's reduced rainfall, it continues to play a crucial role in replenishing the lush landscapes of Hainan, blending the remnants of the summer monsoon with hints of the approaching dry season.
September marks the tail end of Hainan's humid summer, with the humidity hovering around 85%. This figure, while slightly lower than the peak levels of 87% experienced in August, still reflects a significant atmospheric moisture that characterizes the region during this time. The trend is clear: as Hainan transitions from the sweltering months of July and August, the humidity remains notably high, though it begins a gradual decline towards October's 80%. The overall pattern showcases a summer of intense humidity, followed by a slow easing, making September a quintessential time for individuals to experience the lingering tropical warmth before the onset of a more comfortable fall.
In September, Hainan experiences a UV Index of 6, classifying it in the high exposure category with a burn time of 25 minutes. This marks a slight decrease from the very high indices of 8 and 9 seen in the preceding months of July and August. Overall, the trend in Hainan’s UV Index reflects a gradual decline as the year transitions into autumn, easing the intense sun exposure typical of summer. However, with a notably high UV Index still in place, it's essential for visitors and locals alike to remain vigilant about sun safety. For comprehensive UV index insights, visit Hainan UV Index.
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As summer fades and September unfolds in Hainan, sunshine remains abundant, with the island basking in 284 hours of glorious sunlight. This month marks a slight dip from the peak of July's impressive 341 hours, yet still stands as one of the sunniest periods of the year. With sunshine hours gradually tapering off as autumn approaches, visitors can enjoy warm days and vibrant evenings, as Hainan transitions from its sun-drenched summer to a milder fall. The trend reveals a consistent pattern of increasing sunlight from January's 182 hours to May's high of 330 hours, followed by a gradual decrease, making September an ideal time for travelers seeking a last touch of summer warmth before the cooler months set in.
In September, Hainan experiences a 41% chance of sunny weather, marking a slight rise from the rainy summer months, though still lower than the sun-drenched peak of January's 62%. This transitional period is nestled between the last throes of summer and the return of clearer skies in October, which enjoys a 60% likelihood of sunshine. As the year progresses, the trend shows a fluctuating pattern of sunshine, with winter months like December boasting a 68% chance. Thus, while September offers a modest opportunity for warm, sunny days, visitors should prepare for the lingering remnants of summer humidity and occasional showers.
As September ushers in the transition from summer to autumn in Hainan, daylight hours begin to wane, providing 12 hours of sunlight—a gentle decline from the 14 hours experienced in August. This month marks a noticeable shift from the peak summer brightness, which saw a consistent 15 hours of daylight from May through July. The gradual reduction in daylight continues through the fall, culminating in the shorter days of October and November, where sunlight dips to 10 and 9 hours respectively. This trend emphasizes the island's seasonal rhythm, reminding residents and visitors alike of the changing tides of nature as the year progresses.
In September, Hainan experiences a gentle breeze with an average wind speed of 2.7 m/s (6 mph), which is consistent with the quieter summer months of July and August. This modest wind speed seems to echo the transitional nature of early autumn, as it remains lower than the spring peak of 4.0 m/s (9 mph) seen in April. As the island moves into autumn, wind speeds pick up again in October, reaching 3.3 m/s (7 mph), suggesting a refreshing change ahead after the calmer summer days. Overall, the gradual ebb and flow of the wind throughout the year reflects Hainan's dynamic climate, varying from serene summer breezes to spirited autumn gusts.
Weather in Hainan varies notably across the year, with each month offering distinct climate conditions. This page compares September’s weather to other months in Hainan, focusing on differences in temperature, rainfall, humidity, and UV levels.
September and January present stark contrasts in weather. September boasts a mild average temperature of 15°C (59°F), with daytime highs reaching up to 28°C (83°F), while experiencing considerable precipitation of 103 mm (4.1 in) over about 9 days, resulting in a humid atmosphere at 85%. In contrast, January plunges into significantly colder conditions, featuring an average temperature of -20°C (-4°F) and maximums barely rising above freezing at -3°C (27°F). This month sees minimal precipitation, with just 5 mm (0.2 in) over only 1 day, coupled with a lower humidity of 75%. For a detailed comparison, you can also check Hainan weather in January.
September and February showcase stark contrasts in weather conditions. In September, temperatures range from a chilly 0°C (33°F) at night to a warm 28°C (83°F) during the day, with an average of 15°C (59°F). The month typically sees around 103 mm (4.1 in) of rainfall over approximately 9 days and boasts a high humidity level of 85%. In contrast, February is characterized by severe cold, with temperatures dipping as low as -33°C (-27°F) at night and averaging -15°C (5°F) during the day, peaking at a mere 8°C (47°F). The precipitation is minimal at just 6 mm (0.2 in) over 1 day, and humidity sits at 70%. For more specific insights into February weather, see Hainan weather in February.
September and March showcase strikingly different weather patterns. In September, temperatures range from a chilly 0°C (33°F) at night to a pleasant maximum of 28°C (83°F) during the day, with an average of 15°C (59°F). The month also brings significant rainfall, totaling 103 mm (4.1 in) over about 9 days, alongside high humidity levels of 85%. In stark contrast, March experiences much colder conditions, with minimum temperatures plunging to -31°C (-23°F) and an average of -3°C (26°F). The maximum temperature reaches only 17°C (63°F), with minimal precipitation of just 13 mm (0.5 in) across 3 days, accompanied by lower humidity at 63%. This comparison highlights the seasonal shift from the warmth and moisture of late summer to the biting chill of late winter. For more detailed insights, you can check out Hainan weather in March.
September and April present contrasting weather patterns, with September showcasing a milder average temperature of 15°C (59°F) compared to April's cooler average of 7°C (44°F). While September experiences a broader temperature range, with maximums reaching 28°C (83°F), April has chilly lows that can dip down to -9°C (16°F). Precipitation is significantly higher in September, totaling 103 mm (4.1 in) over 9 days, whereas April is much drier, recording only 32 mm (1.3 in) across just 4 days. Additionally, September's higher humidity at 85% contrasts sharply with April’s lower humidity of 59%, highlighting the differences in feel and comfort between the two months. For further details, you can check Hainan weather in April.
In September, the weather typically features a wider temperature range, with minimums dipping to 0°C (33°F) and maximums reaching up to 28°C (83°F), resulting in an average temperature of 15°C (59°F). This month also sees significant rainfall, with approximately 103 mm (4.1 in) of precipitation spread across 9 days, contributing to higher humidity levels at 85%.
In contrast, May experiences a slightly lower average temperature of 14°C (58°F), but the maximum can peak at 31°C (89°F). Although May has a bit more rainy days, the total precipitation is lower at 72 mm (2.8 in), and the humidity is significantly lower at 61%.
For more detailed insights into May's climate, visit Hainan weather in May.
September and June present contrasting weather patterns. In September, temperatures range from a chilly minimum of 0°C (33°F) to a comfortable maximum of 28°C (83°F), with an average of 15°C (59°F). This month also experiences significant rainfall, totaling 103 mm (4.1 in) over 9 days, accompanied by high humidity levels of 85%. In contrast, June boasts warmer temperatures, with a minimum of 6°C (43°F) and a peak of 36°C (97°F), averaging 19°C (67°F). Rainfall is more frequent in June, with 126 mm (4.9 in) spread across 15 days, yet the humidity is slightly lower at 79%. For more detailed insights, you can explore Hainan weather in June.
September's weather brings a cooler climate compared to July, with average temperatures dropping from 23°C (74°F) in July to 15°C (59°F) in September. While July features warmer highs reaching up to 34°C (93°F), September sees a maximum of 28°C (83°F), resulting in a more moderate environment. Precipitation is also noteworthy; July experiences 175 mm (6.9 in) over 17 days, while September has slightly less rainfall at 103 mm (4.1 in) across 9 days. Both months maintain high humidity, with September at 85% and July just a notch lower at 84%. For a detailed look at July weather, you can check out Hainan weather in July.
In comparing the weather between September and August, we see notable differences in temperature and precipitation. September typically experiences cooler temperatures, with a minimum of 0°C (33°F) and an average of 15°C (59°F), contrasting sharply with August's milder conditions that have a minimum of 6°C (42°F) and an average of 20°C (69°F). Additionally, while both months are relatively humid—85% in September and 87% in August—August receives significantly more rainfall, totaling 183 mm (7.2 inches) over 17 days compared to September's 103 mm (4.1 inches) over 9 days. For more details, you can check Hainan weather in August.
In September, the weather is relatively warmer with temperatures ranging from a minimum of 0°C (33°F) to a maximum of 28°C (83°F), accompanied by significant precipitation totaling 103 mm (4.1 in) spread across 9 days and high humidity at 85%. In contrast, October ushers in cooler temperatures, with a minimum of -10°C (15°F) and an average of 6°C (42°F), though it can still reach highs of 27°C (80°F). The precipitation drastically decreases to 22 mm (0.9 in) over just 4 days, and humidity slightly drops to 80%. For more insights into the October weather, you can check Hainan weather in October.
September and November present stark contrasts in weather conditions. In September, temperatures range from a minimum of 0°C (33°F) to a maximum of 28°C (83°F), with an average of 15°C (59°F), creating a warm and humid environment with high humidity at 85% and 103 mm of precipitation over about 9 days. In contrast, November experiences much colder temperatures, with a low of -25°C (-14°F) and an average of -6°C (21°F), peaking at only 14°C (57°F). Precipitation drops dramatically to just 22 mm (0.9 in) over 4 days, and humidity decreases to 61%. For more details about November weather, you can check Hainan weather in November.
September and December present strikingly contrasting weather conditions. In September, temperatures range from a minimum of 0°C (33°F) to a maximum of 28°C (83°F), with an average of 15°C (59°F). This month experiences considerable precipitation of 103 mm (4.1 in) over about 9 days, contributing to a high humidity level of 85%. In contrast, December showcases a much colder climate, where temperatures drop significantly, with a minimum of -32°C (-26°F), an average of -18°C (0°F), and a maximum of just 6°C (43°F). Precipitation is minimal at 9 mm (0.3 in), occurring only over 2 days, and the humidity decreases to 60%. Such drastic differences in temperature and precipitation illustrate the seasonal shift from early fall to deep winter. For more detailed information, visit Hainan weather in December.
September in Hainan showcases a unique transition in weather, setting itself apart from both the sweltering summer and the cooler months ahead. With warm maximum temperatures reaching up to 28°C (83°F) and an average of 15°C (59°F), the island's climate remains inviting. However, it also sees a notable increase in humidity at 85% and precipitation with about 103 mm (4.1 in) of rain over 9 days, hinting at the tail-end of the monsoon season. This blend of warmth and moisture creates a lush, vibrant environment, perfect for those looking to experience Hainan's natural beauty. For a deeper dive into what to expect throughout the year, check out Hainan Climate.