Last updated: August 28, 2025
In September, Ha Long, Vietnam welcomes a tropical climate characterized by warm temperatures and high humidity. With a maximum temperature reaching 35°C (95°F) and an average of 28°C (83°F), the weather can feel quite sultry. Visitors can expect frequent rainfall, as the city experiences about 256 mm (10.1 in) of precipitation over 23 days, contributing to the lush green landscape and vibrant scenery. The humidity level hovers around 82%, making it a month where light clothing and prepared umbrellas are essential for enjoying the breathtaking beauty of this coastal gem.
As September rolls into Ha Long, Vietnam, the weather begins to shift, marking a transition from the hot summer months to a more temperate fall. With minimum temperatures around 22°C (72°F) and a comfortable average of 28°C (83°F), the city enjoys a balmy atmosphere that’s perfect for exploring its stunning limestone landscapes. Though the maximum temperature reaches up to 35°C (95°F), it feels more manageable as humidity levels start to drop. This month signifies a gradual cooldown from the sweltering heat of June and July, providing visitors with a delightful experience without the oppressive heat, making September an ideal time to visit Ha Long's enchanting bay.
In September, Ha Long experiences a significant shift in precipitation patterns, with an average rainfall of 256 mm (10.1 in), marking a substantial decrease from the torrential downpours of August. This month brings 23 rainy days, offering a respite from the earlier intense rainfall but still contributing to the region's lush landscapes. The decrease in moisture compared to August's peak of 521 mm (20.5 in) suggests an easing of the summer monsoon, while still retaining enough humidity to keep the air vibrant with life. As the year progresses, September’s rainfall serves as a reminder of the transitioning seasons, balancing the lushness of summer with the drier trends anticipated in October and November.
As summer wanes in Ha Long, Vietnam, September brings a notable shift in humidity levels, averaging at 82%. This marks a slight drop from the peak 90% experienced in July, but it remains significantly high, reflecting the lingering effects of the monsoon season. Following a trend established earlier in the year, humidity in September tends to fluctuate slightly but generally stays elevated when compared to the drier months of late fall. After experiencing the sweltering summer humidity, residents and visitors might appreciate this small respite, although the air remains thick with moisture, contributing to the region’s lush greenery and vibrant landscape.
In September, Ha Long, Vietnam experiences an extreme UV Index of 13, consistent with the highest readings throughout the summer months. This trend highlights a sustained period of intense sun exposure, where the recommended burn time is a mere 10 minutes. With the UV Index remaining at such elevated levels, it is essential for visitors to prioritize sun safety and protection. Following September, a slight decrease is expected in October; however, caution remains paramount as the UV Index still hovers around 11. To learn more about the UV levels throughout the year, explore Ha Long UV Index.
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September shines brightly in Ha Long, Vietnam, with an impressive 286 hours of sunshine that signals the tail end of summer while hinting at the enchanting autumn ahead. This month follows the summer wave, showcasing comfortably warm weather and vibrant blue skies, just slightly less radiant than May’s peak of 307 hours. As the year progresses, it becomes evident that daylight gradually wanes, transitioning from the sun-soaked highs of mid-year towards the milder hues of autumn. Overall, September’s sun embraces visitors, making it an ideal time to explore Ha Long's spectacular landscapes before the cooler months set in.
In September, the likelihood of sunny weather in Ha Long, Vietnam sits at a modest 24%, revealing a marked dip in sunshine compared to the earlier months of the year. The trend indicates that as summer gives way to autumn, the chances of clear skies decline, particularly when compared to the sunniest months of January and February. After the peak sunshine of late winter, the weather gradually becomes more unpredictable, with August facing the lowest probability at just 12%. This downward trend continues into September, suggesting that visitors might experience more cloudy days or occasional rain. As the year progresses, however, opportunities for sunnier days rise again in late autumn, with October improving slightly to 28% and peaking in the final months.
In September, Ha Long, Vietnam enjoys a delightful 12 hours of daylight, marking a continuation of the summer abundance of light. Following the peak of 13 hours in the earlier months, the daylight duration begins to taper slightly, yet remains generous enough for exploration and relaxation. The gradual decline in daylight hours from mid-summer into early autumn reflects a natural rhythm, as the region transitions towards cooler temperatures. As the year progresses, October will bring a further dip to 11 hours, but September's vibrant days still provide ample opportunity to soak in the stunning landscapes and rich culture before the days grow shorter. This month strikes a perfect balance, allowing both locals and visitors to relish in the scenic beauty of Ha Long.
As September unfolds in Ha Long, Vietnam, the average wind speed gently drops to 2.2 m/s (5 mph), marking a noticeable shift from the breezier summer months. Following the peak of 3.7 m/s (8 mph) seen in May and June, this transition signals the onset of a more tranquil atmosphere, possibly inviting more serene boat excursions and reflective moments by the emerald waters. The prevailing winds, while calmer than earlier in the year, remain a cherished part of Ha Long’s charm, setting the stage for October's invigorating increase to 4.0 m/s (9 mph). This rhythmic ebb and flow of wind speeds not only enhances the natural beauty of the area but also suggests a seasonal shift that both locals and visitors can enjoy.
Weather in Ha Long varies notably across the year, with each month offering distinct climate conditions. This page compares September’s weather to other months in Ha Long, focusing on differences in temperature, rainfall, humidity, and UV levels.
September and January present starkly contrasting weather conditions. In September, temperatures range from a minimum of 22°C (72°F) to a maximum of 35°C (95°F), with an average of 28°C (83°F). This month is characterized by high humidity at 82% and significant rainfall, accumulating 256 mm (10.1 in) over 23 days. In contrast, January experiences much cooler temperatures, with a minimum of 8°C (46°F) and a maximum of 26°C (80°F), averaging 18°C (64°F). Rainfall is minimal during this month, totaling just 28 mm (1.1 in) over only five days, and humidity is lower at 66%. For more details on January weather in Ha Long, check out Ha Long weather in January.
September and February present contrasting weather conditions. In September, temperatures range from a warm 22°C (72°F) at night to a scorching average of 28°C (83°F) during the day, peaking at 35°C (95°F). This month is also marked by significant rainfall, with 256 mm (10.1 in) spread across 23 days, resulting in a high humidity level of 82%. In stark contrast, February experiences much cooler temperatures, with a minimum of 7°C (45°F) and a maximum of 27°C (80°F), averaging 18°C (65°F). Additionally, precipitation is minimal in February, totaling just 36 mm (1.4 in) over 7 days, and the humidity is lower at 71%. For more detailed insights on February weather in Ha Long, you can explore Ha Long weather in February.
In September, the weather is notably warmer and more humid, with temperatures ranging from a minimum of 22°C (72°F) to a maximum of 35°C (95°F) and an average of 28°C (83°F). The month also experiences significant rainfall, totaling 256 mm (10.1 in) over 23 days, contributing to a high humidity level of 82%. In contrast, March offers a milder climate, with temperatures ranging from a minimum of 14°C (57°F) to a maximum of 31°C (88°F) and an average of 21°C (71°F). Precipitation in March is considerably lower at 52 mm (2.0 in) over just 15 days, and humidity levels are more comfortable at 69%. For more detailed insights into March weather, you can visit Ha Long weather in March.
In September, the weather is typically hot and humid, with average temperatures around 28°C (83°F) and highs reaching up to 35°C (95°F). The month experiences significant rainfall, totaling 256 mm (10.1 in) over about 23 days, resulting in a humidity level of 82%. In contrast, April offers a more moderate climate, with average temperatures of 24°C (75°F) and maximums of 33°C (91°F). Precipitation in April is much lower, at 91 mm (3.6 in) over 15 days, and the humidity drops to a comfortable 64%. For more details, you can check Ha Long weather in April.
When comparing the weather in September and May, both months exhibit warm temperatures, though September tends to be slightly hotter on average. September has a minimum temperature of 22°C (72°F) and an average of 28°C (83°F), reaching a maximum of 35°C (95°F). In contrast, May shows a minimum of 19°C (66°F) and averages 27°C (81°F), with highs peaking at 36°C (98°F). While May experiences less rainfall at 184 mm (7.2 in) over 19 days, September sees increased precipitation totaling 256 mm (10.1 in) over 23 days, contributing to a higher humidity level of 82% compared to May's 73%. For more details on weather trends, you can refer to Ha Long weather in May.
In comparing the weather between September and June, we notice that both months experience warm temperatures, but June tends to be slightly hotter. June has an average temperature of 30°C (86°F), reaching a maximum of 38°C (100°F), while September's average is 28°C (83°F), peaking at 35°C (95°F). Additionally, June sees marginally less precipitation at 240 mm (9.4 in) over 20 days, compared to September’s 256 mm (10.1 in) falling over 23 days. Humidity levels are quite similar, with June at 81% and September at 82%. For more detailed insights, you can check Ha Long weather in June.
September experiences slightly cooler temperatures compared to July, with minimums around 22°C (72°F) and a maximum of 35°C (95°F), while July typically sees minimums of 25°C (77°F) and peaks at 36°C (98°F). Although both months are quite humid, September's average humidity is 82%, which is marginally lower than July's 90%. Precipitation is similar in both months, with September receiving 256 mm (10.1 in) over 23 days, while July has a bit more at 287 mm (11.3 in) over 24 days. For more detailed information, you can check Ha Long weather in July.
In comparing the weather between September and August, both months maintain an average temperature of 28°C (83°F), but September experiences slightly cooler minimum and maximum temperatures, ranging from 22°C (72°F) to 35°C (95°F), compared to August's range of 24°C (76°F) to 36°C (97°F). Precipitation levels are notably lower in September, with 256 mm (10.1 in) over 23 days, contrasting with August's significant rainfall of 521 mm (20.5 in) across 28 days. Furthermore, September's humidity is slightly reduced at 82% compared to August's higher level of 89%. For more details on August's weather, you can check this link: Ha Long weather in August.
September weather tends to be hotter and more humid, with temperatures ranging from a minimum of 22°C (72°F) to a maximum of 35°C (95°F) and an average temperature of 28°C (83°F). The month also experiences significant rainfall, totaling 256 mm (10.1 in) across 23 days, contributing to a high humidity level of 82%. In contrast, October brings a slight decrease in temperature, with minimums of 17°C (63°F), an average of 25°C (77°F), and maximums of 34°C (94°F). Precipitation is also reduced in October, totaling 204 mm (8.0 in) over 16 days, while humidity levels drop to 77%. For more detailed information, you can check Ha Long weather in October.
September and November present contrasting weather conditions. September tends to be much warmer, with temperatures ranging from a minimum of 22°C (72°F) to a maximum of 35°C (95°F) and an average of 28°C (83°F). The month is characterized by high humidity at 82% and significant precipitation, totaling 256 mm (10.1 in) over 23 rainy days. In contrast, November brings a more comfortable climate, with temperatures cooling down to a minimum of 12°C (54°F), a maximum of 30°C (86°F), and an average of 22°C (73°F). Rainfall is significantly reduced to just 43 mm (1.7 in) across 9 days, accompanied by lower humidity at 72%. For more detailed insights on weather conditions, you can check Ha Long weather in November.
In September, the weather is significantly warmer and more humid, with temperatures ranging from a minimum of 22°C (72°F) to a high of 35°C (95°F). The month also sees considerable rainfall, with an average of 256 mm (10.1 in) spread over 23 days, contributing to a high humidity level of 82%. In contrast, December experiences much cooler temperatures, with a minimum of 8°C (46°F) and a maximum of 28°C (82°F), leading to a more comfortable average of 18°C (66°F). Precipitation in December is markedly lower, with only 31 mm (1.2 in) of rain over just 6 days, and humidity decreases to 71%. For more specific insights into December's climate, you can refer to Ha Long weather in December.
In September, Ha Long experiences a notable shift in its weather profile compared to the drier summer months. With an average temperature lingering around a warm 28°C (83°F), the days can still feel quite hot, peaking at 35°C (95°F), while the nights offer a mild respite. However, this month also ushers in a significant increase in precipitation, with rain gracing the area on roughly 23 days, leading to a total of 256 mm. The elevated humidity level, reaching 82%, creates a tropical atmosphere that can feel heavy at times. For those intrigued by Ha Long's climate intricacies, more details are available in our comprehensive guide on Ha Long Climate.