Last updated: August 27, 2025
September in Chiang Mai, Thailand offers a blend of warm temperatures and considerable rainfall, making it a vibrant time for the region. With a maximum temperature reaching 35°C (95°F) and an average of 27°C (81°F), days can be quite warm despite the frequent showers. The month sees an impressive 198 mm (7.8 in) of precipitation, distributed over approximately 21 days, contributing to the lush greenery that defines the area. Humidity levels hover around 83%, creating a tropical atmosphere that enhances the beauty and charm of Chiang Mai. Whether you're exploring the rich cultural heritage or enjoying the natural landscapes, September's weather adds a unique twist to your experience.
In September, Chiang Mai experiences a shift in its warm climate, with temperatures averaging 27°C (81°F). The month starts to cool slightly compared to the peak summer months, as the minimum temperature hovers around 22°C (71°F) and the maximum reaches 35°C (95°F). This marks a transition from the sweltering highs of summer, creating a more comfortable atmosphere for both locals and visitors. As the rain begins to taper off towards the end of the month, the city's lush landscapes flourish, setting the perfect backdrop for exploring its rich culture and stunning scenery. Overall, September showcases a pleasant harmony of warmth and a refreshing breeze, inviting you to indulge in Chiang Mai’s enchanting offerings.
September marks a significant shift in precipitation patterns for Chiang Mai, Thailand, as the city emerges from the peak rainy season. With 198 mm (7.8 in) of rainfall over 21 days, September continues the trend set in August, though with a noticeable decrease. This month captures the essence of the monsoon's tapering, where the lush landscapes enjoy a final surge of moisture before transitioning into a drier season. Compared to the torrential rains of July and August, September's precipitation serves as a gentle reminder of the seasonal ebb and flow that sustains the region's vibrant ecosystem, making it a pivotal time for agriculture and natural replenishment.
September in Chiang Mai marks the tail end of the monsoon season, where humidity remains elevated at 83%. This month's figures reflect a trend of increasing moisture that begins in May and peaks in August, creating a stifling atmosphere throughout the mid-year. As the rains begin to taper off, September also serves as a transition towards drier air, with humidity levels gradually decreasing as the year progresses into October and November. Travelers and locals alike can expect a sticky ambience, yet the lush greenery and vibrant landscapes brought on by the heavy rains provide a stunning backdrop during this time.
As September rolls in, Chiang Mai continues to bask under a relentless sun, with a UV Index of 14, marking it as part of the extreme exposure category. This means that visitors and residents alike should be cautious, as the burn time is only 10 minutes. Following the trends of the preceding months, where similar levels have been recorded, September solidifies its position in a summer characterized by high UV levels. With the potential for skin damage increasing, it’s vital to prioritize sun protection during this time. To stay informed and safe, check out the detailed insights here: Chiang Mai UV Index.
UV Risk Categories
September in Chiang Mai, Thailand, offers a delightful 262 hours of sunshine, striking a balance between the bright, sun-drenched days of summer and the gradual transition into the cooler months. While this month experiences a slight dip compared to the sun-soaked peak of March with 338 hours, it outshines the more overcast days of the preceding August. This transition reflects a broader trend: as the year progresses, sunshine peaks in early spring and gradually lessens through the wet season, with October and November bringing back more sunlight before winter settles in. So, visitors can enjoy September's pleasant weather, perfect for exploring Chiang Mai’s vibrant culture and stunning landscapes.
September in Chiang Mai sees a marked dip in sunny weather, with a mere 20% chance of clear skies. This is a significant decline from the sun-soaked months of January through April, where opportunities to bask in the sun are above 75%. Following the vibrant sunny days of early in the year, the onset of the rainy season in May leads to a dramatic increase in cloud cover, culminating in the damp months of June through August, where sunshine chances plummet to around 11-12%. As September rolls in, lingering monsoon clouds continue to overshadow the region, leading to a brisk 20% likelihood of sunshine, signaling that travelers should be prepared for the possibility of rain during their visit. As the month transitions into October, the promise of clearer skies begins to emerge again, giving hope for those looking to soak up some sun in the heart of Northern Thailand.
As September unfolds in Chiang Mai, Thailand, the city enjoys a wholesome 12 hours of daylight, marking a transition from the longer days of summer. Following a peak in May, where daylight extends to 13 hours, the trend shifts downwards slightly as the year progresses. With daylight reducing to 12 hours in both September and August, the rhythms of daily life begin to align more closely with the cooler and shorter days of autumn. This gradual tapering—starting from 11 hours in January and February and peaking in the hotter months—provides a rhythm that residents and visitors alike savor, as the vibrant cultural and natural landscape of Chiang Mai evolves with the seasons.
In September, the winds in Chiang Mai, Thailand, begin to soften, with an average speed of just 1.0 m/s (2 mph), marking the lowest point in the annual wind cycle. This gentle breeze, a prelude to the tranquil transition into the dry season, contrasts with the slightly stronger winds of previous months. As the rainy season approaches its end, the subtle decrease in wind speed reflects a calmness that envelops the city, inviting residents and visitors alike to embrace the peaceful ambiance. The consistent wind patterns throughout the year highlight a seasonal rhythm that seamlessly blends with the vibrant culture and stunning landscapes of Chiang Mai, making September an enchanting time to experience the city's charm.
Weather in Chiang Mai varies notably across the year, with each month offering distinct climate conditions. This page compares September’s weather to other months in Chiang Mai, focusing on differences in temperature, rainfall, humidity, and UV levels.
September and January present contrasting weather patterns. In September, the temperatures range from a mild 22°C (71°F) to a scorching 35°C (95°F), with an average of 27°C (81°F) and significant rainfall totaling 198 mm (7.8 in) over 21 days, accompanied by high humidity at 83%. In stark contrast, January features much cooler temperatures, with a minimum of 10°C (51°F), an average of 22°C (72°F), and a maximum of 34°C (93°F). Precipitation is minimal, with only 10 mm (0.4 in) over just 2 days, and humidity drops to a more comfortable 51%. For further details on January weather, check out Chiang Mai weather in January.
September and February showcase contrasting weather patterns. In September, temperatures range from a minimum of 22°C (71°F) to a maximum of 35°C (95°F), with an average of 27°C (81°F). The month is notably wet, experiencing 198 mm (7.8 in) of precipitation over 21 days and high humidity at 83%. In stark contrast, February boasts milder temperatures, with a minimum of 11°C (53°F), an average of 24°C (75°F), and a high reaching 36°C (97°F). This month sees nearly negligible rainfall, with only 2 mm (0.1 in) and no rainy days, along with a significantly lower humidity level of 46%. For more details, check out Chiang Mai weather in February.
The weather in September is characterized by warmer temperatures and significantly higher humidity compared to March. In September, the average temperature hovers around 27°C (81°F), with maximum temperatures reaching up to 35°C (95°F). However, it also experiences considerable rainfall, with around 198 mm (7.8 in) falling over 21 days, resulting in a humid environment with an average humidity of 83%.
In contrast, March sees a slightly cooler minimum temperature of 16°C (60°F) but can reach a scorching maximum of 40°C (104°F). Remarkably, March has minimal precipitation, with just 1 mm (0.1 in) recorded over the month and no rainy days, leading to much lower humidity levels at 38%. For more details, you can refer to Chiang Mai weather in March.
In September, temperatures range from a minimum of 22°C (71°F) to a maximum of 35°C (95°F), with an average of 27°C (81°F). This month is characterized by significant rainfall, receiving approximately 198 mm (7.8 in) over 21 days, accompanied by high humidity at 83%. In contrast, April experiences warmer conditions with a minimum of 18°C (65°F) and a striking maximum of 42°C (107°F), averaging around 29°C (85°F). Rainfall is minimal in April, totaling only 42 mm (1.7 in) over just 6 days, and the humidity drops to a comfortable 36%. For more information on the weather patterns, visit Chiang Mai weather in April.
When comparing the weather in September and May, significant differences emerge. September tends to be more humid, with an average temperature of 27°C (81°F) and a maximum reaching 35°C (95°F), while experiencing considerable rainfall of 198 mm (7.8 in) over 21 days. In contrast, May is slightly warmer, featuring a minimum temperature of 23°C (73°F) and an average of 30°C (86°F), peaking at a scorching 41°C (106°F). The precipitation in May is considerably lower at 82 mm (3.2 in), falling over just 9 days, and the humidity is also less, sitting at a more comfortable 63%. For more details, check out Chiang Mai weather in May.
When comparing the weather in September and June, notable differences emerge. In September, temperatures range from a minimum of 22°C (71°F) to a maximum of 35°C (95°F), with an average temperature of 27°C (81°F). This month experiences higher rainfall, averaging 198 mm (7.8 in) across 21 days, coupled with humidity levels at 83%. In contrast, June boasts slightly warmer temperatures, with a minimum of 23°C (74°F), an average of 29°C (84°F), and a scorching maximum of 40°C (104°F). Additionally, June has less precipitation, averaging 145 mm (5.7 in) over 17 days, with a slightly lower humidity of 81%. For more details, you can check Chiang Mai weather in June.
When comparing the weather in September and July, both months exhibit high temperatures and significant humidity, though there are some notable differences. In July, temperatures range from a minimum of 23°C (73°F) to a maximum of 40°C (104°F), making it the hotter month overall, with an average temperature of 28°C (83°F). September, on the other hand, features slightly lower temperatures, with a minimum of 22°C (71°F) and a maximum of 35°C (95°F), averaging 27°C (81°F). Additionally, July receives slightly more precipitation at 218 mm (8.6 in) over 22 days compared to September's 198 mm (7.8 in) over 21 days. Both months maintain humidity levels around 83%, contributing to their tropical climate. For a detailed overview of conditions, you can check out Chiang Mai weather in July.
In comparing the weather of September and August, September brings slightly cooler temperatures, with a minimum of 22°C (71°F) compared to August's minimum of 23°C (73°F). The average temperature remains consistent at 27°C (81°F), but August records a slightly higher maximum of 36°C (97°F) versus September's maximum of 35°C (95°F). While September experiences less precipitation at 198 mm (7.8 in) over 21 days, August sees a higher total of 268 mm (10.5 in) across 26 days. Humidity levels also drop in September to 83%, compared to 91% in August, making the transition into fall a bit drier and less humid. For more details, see Chiang Mai weather in August.
In comparing the weather between September and October, we notice a slight decrease in temperatures as October features a minimum of 20°C (69°F) and an average of 26°C (80°F), compared to September's minimum of 22°C (71°F) and average of 27°C (81°F). While September peaks at a maximum of 35°C (95°F), October’s maximum temperature is a bit lower at 34°C (94°F). Additionally, precipitation levels decrease from 198 mm (7.8 in) over 21 days in September to 156 mm (6.1 in) over 18 days in October, leading to a drop in humidity from 83% to 67%. This transition marks the beginning of drier conditions as the weeks progress. For more detailed information, check out Chiang Mai weather in October.
September and November exhibit notable differences in weather patterns. In September, temperatures are quite warm, with a minimum of 22°C (71°F) and an average of 27°C (81°F), but can peak at a maximum of 35°C (95°F). This month is also characterized by high humidity levels at 83% and significant rainfall, totaling 198 mm (7.8 in) over 21 days. In contrast, November experiences cooler temperatures, with a minimum of 13°C (56°F), an average of 25°C (77°F), and a maximum of 34°C (93°F). This month features much less precipitation, accumulating only 24 mm (0.9 in) across just 5 days, alongside a drop in humidity to 60%. For more detailed insights, you can check Chiang Mai weather in November.
September weather is characterized by warmer temperatures, with a minimum of 22°C (71°F), an average of 27°C (81°F), and a peak of 35°C (95°F). This month also brings significant rainfall, totaling 198 mm (7.8 in) over 21 days, accompanied by high humidity levels at 83%. In contrast, December experiences much cooler temperatures, with a minimum of 6°C (43°F), an average of 21°C (71°F), and a maximum of 33°C (91°F). Precipitation drops dramatically to just 13 mm (0.5 in) over a single day, and humidity decreases to 56%. For more details, you can check out Chiang Mai weather in December.
September in Chiang Mai is characterized by its lush greenery and high humidity, setting it apart from other months in the region. The substantial rainfall, averaging around 198 mm over 21 days, creates a vibrant atmosphere but can also lead to tropical downpours. Temperatures remain warm, with an average of 27°C, which, combined with the high humidity at 83%, can make the air feel heavier. While this might deter some visitors, those who embrace the wet season will enjoy the quieter attractions and the stunning, rejuvenated landscapes. For a deeper understanding of what to expect throughout the year, explore Chiang Mai Climate.