Last updated: August 28, 2025
In September, Son La, Vietnam experiences a blend of warm temperatures and significant rainfall, making it a unique month for both locals and visitors. Daily maximums can reach 34°C (94°F), while the average hovers around a comfortable 25°C (78°F). The cooler evenings, where temperatures can dip to 17°C (63°F), provide a welcome respite. This month sees approximately 121 mm (4.8 in) of precipitation spread over 19 days, contributing to the region's lush landscapes. With humidity levels soaring to 82%, September in Son La is characterized by a vibrant, yet moist atmosphere, perfect for experiencing the natural beauty and dynamic culture of the area.
In September, Son La experiences a transition in temperatures, providing a refreshing break from the summer heat. The minimum temperature settles at a comfortable 17°C (63°F), while the average rises to a pleasant 25°C (78°F), peaking at a maximum of 34°C (94°F). This month marks a noticeable cooling trend, especially compared to the sweltering highs of May and June, where temperatures reached upwards of 38°C (101°F). As the region approaches autumn, the drop in temperatures invites a more enjoyable climate, making September a particularly appealing time for travelers seeking the stunning natural beauty of Son La without the intense heat of summer.
In September, Son La experiences a significant shift in its weather patterns, receiving 121 mm (4.8 in) of precipitation over 19 days. This month marks a notable decrease from the peak rainfall of 322 mm (12.7 in) seen in August, while still maintaining high levels of moisture that support the region's lush landscapes. Following a summer filled with abundant rainfall, September serves as a transitional period, blending the lingering monsoon atmosphere with hints of the approaching drier season. The combination of decreased precipitation days and fluctuating totals indicates a gradual shift towards the more temperate months ahead, making September a pivotal month in the seasonal rhythm of Son La's climate.
In September, Son La, Vietnam experiences a notable shift in humidity levels, marked by an average of 82%. This period continues the trend of peak humidity that starts in the warmer summer months, reaching a high of 92% in August. As the region transitions from the sultry atmospheres of July and August, September still retains significant moisture in the air, albeit slightly less pronounced than the preceding months. Following September, humidity begins to gradually decline, hinting at the cooler, drier months ahead. This fluctuation showcases the characteristic wet tropical climate of the region, where humidity often dictates the seasonal rhythm.
In September, Son La, Vietnam, experiences a consistently high UV Index of 14, categorizing exposure as extreme with a burn time of just 10 minutes. This trend of elevated UV levels has persisted since May, where the index first reached this peak, and notably continues through to October. As the summer months transition into fall, residents and visitors alike should remain vigilant in protecting themselves from harmful UV radiation. With the importance of sun safety accentuated during this time, it's essential to stay informed and prepared. For more detailed insights into UV levels throughout the year, check out the Son La UV Index.
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September in Son La, Vietnam, shines brightly with 285 hours of sunshine, continuing a trend of ample sunlight as summer winds down. Following a peak in May with 312 hours, the sun-soaked days begin to gradually taper off, but September still boasts an impressive total that reflects the region's vibrant weather. The transition from August's 267 hours to September's figure signifies a smooth continuation of warm days, making it an ideal time for outdoor activities and enjoying the lush landscapes. As the year progresses towards autumn, the overall pattern reveals a consistent bounty of sunlight, inviting both locals and visitors to bask in the beauty of Son La’s picturesque scenery.
In Son La, Vietnam, the likelihood of sunny days in September stands at a moderate 29%, reflecting a gradual recovery from the dismal sunshine of the preceding summer months. While this rate is higher than the particularly gloomy periods of June (10%), July (18%), and August (14%), it still falls short of the brighter outlook found in the earlier months of the year, such as March (48%) and the sunny heights of December (55%). This trend suggests that September ushers in a transitional phase, where the likelihood of clear skies begins to increase, hinting at the promise of more pleasant weather as the year progresses. For those planning a visit, this indicates a mix of sun and clouds, offering opportunities to enjoy the rich landscapes of Son La amidst the onset of the dry season.
In Son La, Vietnam, the daylight duration shows an interesting seasonal pattern throughout the year. Starting in January with about 10 hours of daylight, the days gradually lengthen, peaking at 13 hours from May to July. This extended daylight aligns with the region's vibrant summer months, allowing for more time to enjoy the outdoors. As August arrives, daylight begins to wane slightly, settling at 12 hours in September, reflecting a gentle transition towards the cooler autumn months. The days subsequently shorten again in October and November, ultimately returning to 10 hours by December. This rhythmic ebb and flow of daylight not only marks the shifting seasons but also enriches the daily life and activities of the residents in Son La.
As September rolls into Son La, Vietnam, the winds begin to whisper a gentle farewell to the summer heat, with the average wind speed dipping to 1.1 m/s (3 mph). This trend reflects a subtle shift in the seasonal rhythm, where the gusts become softer compared to the earlier months of the year. From January's brisk 1.8 m/s to the almost calm September, it’s clear that the region experiences a gradual decline in wind activity as it transitions into the heart of the autumn season. Though the winds may be less forceful, they still carry with them the promise of change, hinting at the vibrant foliage and cooler temperatures that await in the months ahead.
Weather in Son La varies notably across the year, with each month offering distinct climate conditions. This page compares September’s weather to other months in Son La, focusing on differences in temperature, rainfall, humidity, and UV levels.
In September, the weather is notably warmer and more humid, with average temperatures ranging from a minimum of 17°C (63°F) to a maximum of 34°C (94°F). During this month, rainfall is frequent, with precipitation occurring on 19 days and totaling 121 mm (4.8 in), contributing to an average humidity level of 82%. In contrast, January features a significant drop in temperatures, with averages between 6°C (43°F) and 31°C (88°F). This month experiences much less rainfall, totaling only 34 mm (1.4 in), and precipitation occurs on just 5 days, resulting in a lower humidity of 63%. For more detailed information, you can check Son La weather in January.
In September, the weather is generally warm and humid, with temperatures ranging from a minimum of 17°C (63°F) to a maximum of 34°C (94°F) and an average of 25°C (78°F). The month experiences a significant amount of rainfall, totaling 121 mm (4.8 in) over 19 days, which contributes to the high humidity level of 82%.
In contrast, February brings cooler temperatures, with a minimum of 7°C (45°F) and an average of 18°C (64°F), peaking at 33°C (92°F). Rainfall is considerably lower at just 25 mm (1.0 in) across only 3 days, leading to reduced humidity levels of 65%. For more details, check out Son La weather in February.
September and March present contrasting weather patterns. In September, temperatures range from a minimum of 17°C (63°F) to a warm average of 25°C (78°F), peaking at a hot 34°C (94°F). This month is characterized by significant rainfall, with 121 mm (4.8 in) of precipitation spread over 19 days and high humidity levels at 82%. In contrast, March has a slightly cooler minimum temperature of 11°C (53°F) and a pleasant average of 22°C (71°F), with a similar maximum of 34°C (93°F). Precipitation in March is considerably lower at 67 mm (2.6 in) over just 9 days, and humidity drops to a more comfortable 57%. For a detailed look at March weather in Son La, visit Son La weather in March.
In comparing the weather of September and April, notable differences emerge in both temperature and humidity levels. September generally experiences warmer temperatures, with a minimum of 17°C (63°F) and an average of 25°C (78°F), peaking at a maximum of 34°C (94°F). This month also sees higher humidity, averaging 82%, and a significant amount of rainfall, with 121 mm (4.8 in) spread over 19 days.
In contrast, April presents milder conditions with cooler mornings, featuring a minimum temperature of 11°C (52°F) and an average of 23°C (74°F), while the maximum can reach up to 37°C (99°F). Rainfall during April is less, totaling 103 mm (4.0 in) over 13 days, and with lower humidity at 50%. For a closer look at the weather specifics of April, you can refer to Son La weather in April.
September and May exhibit notable differences in weather patterns. In September, temperatures range from a minimum of 17°C (63°F) to a maximum of 34°C (94°F), while May experiences slightly warmer conditions with a minimum of 16°C (61°F) and a peak of 38°C (101°F). Precipitation is heavier in September, totaling 121 mm (4.8 in) over 19 days, compared to 102 mm (4.0 in) across 16 days in May. Additionally, September's humidity is higher at 82%, making it feel more muggy, while May’s humidity sits at a more comfortable 68%. For more detailed insights into weather conditions, you can check Son La weather in May.
In comparing the weather patterns of September and June, September generally exhibits slightly cooler temperatures, with a minimum of 17°C and an average of 25°C, while June starts warmer, featuring a minimum of 21°C and an average of 27°C. However, June reaches higher maximum temperatures, soaring to 37°C compared to September's maximum of 34°C. Precipitation is more pronounced in June, with 178 mm over 24 days, compared to September's 121 mm over 19 days. Humidity levels remain relatively high in both months, with September at 82% and June slightly lower at 79%. For more details on the weather, you can check Son La weather in June.
In comparing September and July weather, September offers a slightly cooler climate with average temperatures ranging from 17°C (63°F) to a maximum of 34°C (94°F), compared to July's warmer range of 21°C (70°F) to 35°C (95°F). Although September has a lower overall average temperature, it still experiences significant rainfall, with 121 mm (4.8 in) of precipitation across 19 days, while July is characterized by heavier precipitation at 285 mm (11.2 in) over 23 days. Additionally, humidity levels are elevated in both months, with September at 82% and July at 91%, contributing to a somewhat steamy atmosphere during the summer peak. For a more detailed view of July's weather, you can visit Son La weather in July.
In comparing the weather of September and August, September tends to be slightly cooler with average temperatures ranging from a minimum of 17°C (63°F) to a maximum of 34°C (94°F), while August sees a higher minimum of 21°C (70°F) and a close maximum of 33°C (92°F), resulting in an average temperature of 26°C (78°F). Precipitation levels also differ significantly, with September receiving 121 mm (4.8 in) over 19 days compared to August's much wetter conditions of 322 mm (12.7 in) over 26 days. Additionally, humidity remains high throughout both months, but August has a slightly higher average of 92% compared to September's 82%. For more detailed information, you can visit Son La weather in August.
In September, the weather tends to be warmer with average temperatures around 25°C (78°F), reaching highs of 34°C (94°F) and lows of 17°C (63°F). This month also sees considerable precipitation, averaging 121 mm (4.8 in) over 19 days, along with higher humidity at 82%. In contrast, October experiences slightly cooler conditions with an average temperature of 23°C (73°F), peaking at 33°C (91°F) and dipping to a minimum of 12°C (54°F). Rainfall decreases to 103 mm (4.0 in) over 13 days, and humidity levels drop to 76%. For more detailed weather specifics, you can check Son La weather in October.
September and November exhibit notable differences in weather patterns. In September, temperatures range from a minimum of 17°C (63°F) to a maximum of 34°C (94°F), with an average of 25°C (78°F) and significant rainfall totaling 121 mm (4.8 in) over 19 days, resulting in high humidity levels at 82%. In contrast, November experiences cooler temperatures, with a minimum of 9°C (49°F), an average of 20°C (69°F), and a maximum of 31°C (89°F). Precipitation drops dramatically to just 18 mm (0.7 in) over 4 days, and the humidity decreases to 72%. For a detailed view of the November climate, check out Son La weather in November.
September and December present contrasting weather patterns. In September, temperatures range from a minimum of 17°C (63°F) to a maximum of 34°C (94°F), with an average of 25°C (78°F). This month typically sees high humidity at 82% and considerable rainfall, accumulating 121 mm over about 19 days. In contrast, December offers cooler temperatures, with a minimum of 3°C (37°F), an average of 16°C (62°F), and a maximum of 31°C (89°F). The precipitation drops significantly to just 25 mm over 4 days, and humidity decreases to 68%. For a closer look at December weather specifics, visit Son La weather in December.
September in Son La heralds the transition to a cooler season, offering a refreshing change from the summer highs. With average temperatures settling around a pleasant 25°C (78°F), the days are warm but not oppressive. However, this month is also characterized by increased humidity at 82%, creating a lush, vibrant atmosphere as rainfall totals rise, resulting in about 121 mm (4.8 in) of precipitation over roughly half the days. This combination of warmth and moisture distinguishes September from both the scorching summer months and the cooler fall, making it an ideal time to experience the region's natural beauty. For more details about the seasonal patterns, check out Son La Climate.