September Weather in Bangkok, Thailand

Last updated: August 27, 2025

In September, Bangkok, Thailand experiences a tropical climate characterized by warm temperatures and high humidity. The maximum daily temperature reaches around 36°C (97°F) while the average hovers around 29°C (84°F), providing a consistently warm atmosphere. Nighttime brings some relief with minimum temperatures of 24°C (76°F). However, this month is also marked by significant precipitation, with a total of 245 mm (9.6 in) of rainfall spread over approximately 24 days. The high humidity levels, averaging at 87%, contribute to a muggy feeling throughout the day, making it essential for visitors to stay hydrated and seek shelter during sudden rain showers.

September Temperature in Bangkok

In September, Bangkok experiences a warm and inviting climate, with temperatures that start to cool slightly from the oppressive summer heat. The minimum temperature hovers around 24°C (76°F), providing a comfortable start to the day, while the average temperature remains steady at 29°C (84°F)—consistent with the months prior. Daytime highs reach up to 36°C (97°F), still warm but slightly more bearable than the peak heat of April and May. Compared to the summer months of July and August, September's weather presents a subtle transition, hinting at the approaching cool season while still embracing the tropics' characteristic warmth and humidity. Travelers will find a vibrant city atmosphere that's lively yet comfortably warm.

September Weather in Bangkok: Daily Temperature Highs, Lows, and Averages

The chart illustrates September temperature patterns in Bangkok, showcasing daily minimum, maximum, and average temperatures. It highlights the typical range of temperatures throughout the month, providing insights into weather trends. In Bangkok, September typically has an average temperature of {2}°C ({3}°F), with highs reaching up to {4}°C ({5}°F) and lows dropping to around {6}°C ({7}°F).
JanFebMarAprMayJunJulAugSepOctNovDec808285868686858584838280
Data source: Temperature data for Bangkok generated using information from the Copernicus Climate Change Service.
Choose your preferred temperature unit
The average of daily temperatures (24 hours) calculated across all days in the month.

September Precipitation in Bangkok

September in Bangkok marks a peak in the annual rainfall, with 245 mm (9.6 in) of precipitation falling over 24 days. This month typically sees an intensification of the monsoon, surpassing even the downpours of August, which recorded 163 mm. As the atmosphere swells with moisture, the city experiences frequent, heavy showers, contributing to the overall wet season that stretches from May through October. The trend shows a significant increase in precipitation, highlighting September as a crucial month for replenishing water sources and sustaining the lush greenery that characterizes the Thai capital. As the skies open up, the vibrant life of Bangkok continues, demonstrating the resilience and adaptability of the city amidst its seasonal deluge.

September Precipitation Trends in Bangkok

The chart displays monthly precipitation patterns in Bangkok, with values for each month alongside September’s data, which is highlighted for easy comparison. It shows the amount of precipitation, providing insights into how September’s conditions compare to those of other months. In Bangkok, September typically receives around {2} mm ({3} inches) of precipitation spread over approximately {4} days.
JanFebMarAprMayJunJulAugSepOctNovDec2914441071421121591632452506124
Data source: Precipitation data for September generated using information from the Copernicus Climate Change Service.
Choose your preferred precipitation unit

September Humidity in Bangkok

In September, Bangkok experiences a notable humidity level of 87%, marking a slight decrease from the peak of 88% in August. This month showcases a characteristic build-up of moisture as the rainy season approaches its peak, resulting in a muggy atmosphere that many locals and visitors alike feel. As the year progresses from the dry winter months, where humidity hovers around 59-58%, Bangkok transitions into a more humid wet phase, with levels climbing significantly from April onward. The trend reflects a natural rhythmic cycle, where humidity typically peaks during the mid-year months and gradually tapers off as the cooler months return.

September Average Humidity in Bangkok

This chart illustrates the average monthly humidity levels in Bangkok, with September’s data highlighted for easy comparison. It shows the fluctuation in humidity throughout the year, helping you understand how conditions vary by season. In September, average humidity in Bangkok is approximately {2}%, offering insight into how humid the weather typically is during this month.
JanFebMarAprMayJunJulAugSepOctNovDec59%58%61%70%80%85%86%88%87%83%78%70%
Data source: Humidity data for September generated using information from the Copernicus Climate Change Service.

September UV Index in Bangkok

September in Bangkok sees a UV Index of 13, placing it in the extreme exposure category, with a rapid burn time of just 10 minutes. This month continues the trend of high UV levels that dominate Thailand's capital throughout the dry season, peaking with indices of 14 in July and August. While September marks a slight dip from those scorching heights, the risks remain significant, urging residents and visitors alike to take necessary precautions. As the year transitions into the cooler months, the UV Index is expected to gradually decrease, but vigilance is still key. For more detailed information on UV levels throughout the year, check out Bangkok UV Index.

Maximum UV Index Levels in Bangkok for September

The chart shows the monthly maximum UV Index (UVI) for Bangkok in September, representing the highest UV radiation level. The UVI measures the intensity of ultraviolet radiation from the sun, indicating the potential risk of sunburn and UV-related health issues. In September, the maximum UV index in Bangkok typically reaches {2}, which falls under the {3} exposure category.
JanFebMarAprMayJunJulAugSepOctNovDec1012141314131414131298
Data source: Bangkok September UVI data generated using information from the Copernicus Climate Change Service.

UV Risk Categories

  •  Extreme (11+): Avoid the sun, stay in shade.
  •  Very High (8-10): Limit sun exposure.
  •  High (6-7): Use SPF 30+ and protective clothing.
  •  Moderate (3-5): Midday shade recommended.
  •  Low (0-2): No protection needed.

September Sunshine in Bangkok

In September, Bangkok enjoys a warm embrace of 268 hours of sunshine, marking a gradual decline from the peak brightness of March with 336 hours. As the rainy season creeps in, the city experiences fewer sunlit days compared to the prior summer months, yet it still boasts a generous share of sunlight. The weather remains predominantly warm, inviting both locals and tourists to revel in outdoor activities during the day. Interestingly, this slight reduction in sunshine aligns with a broader trend observed throughout the year, where sunlight diminishes from the summer peak and picks up again toward the end of the year. Despite the decrease in sun hours, September still radiates a vibrant atmosphere, making it a unique time to explore the bustling city.

Monthly Sunshine Duration in Bangkok: September Highlighted

The September sunshine duration represents the total number of hours Bangkok experiences direct sunlight during the month of September, excluding cloudy or obstructed periods. This chart compares the sunshine duration of September with the other months of the year.
JanFebMarAprMayJunJulAugSepOctNovDec251h299h336h322h321h302h290h280h268h287h294h316h
Data source: Bangkok September Sunshine duration data generated using information from the Copernicus Climate Change Service.

Chance of Sun in Bangkok During September

September in Bangkok, Thailand, presents a notable decline in sunny weather, with the likelihood of clear skies plummeting to just 10%. This trend is part of a broader pattern, as the city experiences its most overcast months during the rainy season, from June to August, where chances of sunshine are dramatically low. Following this trend, September continues the trend of unfavorable conditions, making it one of the least dependable months for sun-seekers. As the month progresses, residents and visitors alike may want to prepare for the occasional downpour rather than basking in the sun.

Percentage of Sunny Days in September in Bangkok

The chart illustrates the percentage of sunny days in Bangkok throughout the year, with September highlighted. It highlights the variation in sunshine across each month and provides an overview of the typical frequency of sunny days, offering insights into how often Bangkok experiences clear skies throughout the year.
JanFebMarAprMayJunJulAugSepOctNovDec58%76%57%18%33%17%11%9%10%14%29%63%
Data source: Bangkok September chance of sun data, generated using information from the Copernicus Climate Change Service.

Daylight Hours in Bangkok in September

In September, Bangkok enjoys a steady 12 hours of daylight, a continuation of the trend established throughout the wet season. As the city transitions from the sweltering summer, it maintains this consistent daylight duration, which has been characteristic since March. This balance of light plays a crucial role in the vibrant atmosphere of the city, allowing locals and tourists alike to explore its rich culture and bustling streets. Following September, daylight begins to taper off slightly in October, hinting at the subtle shifts of the seasons in this tropical haven. The relatively stable daylight hours from March to September not only highlight Bangkok's unique climatic conditions but also set the stage for its lively and dynamic environment.

Average Daylight Hours in Bangkok for September

The chart illustrates the variation in daylight duration in Bangkok throughout the year, with September highlighted. It shows the monthly changes in daylight hours, calculated by summing the hours between sunrise and sunset.
JanFebMarAprMayJunJulAugSepOctNovDec11h 24m11h 40m12h 2m12h 25m12h 45m12h 54m12h 49m12h 33m12h 11m11h 48m11h 28m11h 19m
Data source: Bangkok daylight hours, calculated by summing the hours between sunrise and sunset for each day.

September Winds in Bangkok

As the calendar turns to September in Bangkok, the average wind speed gently settles at 2.0 m/s (5 mph), reflecting a subtle decline from the summer breezes of June (3.0 m/s) and July (2.7 m/s). The typically humid atmosphere begins to dance with the slightest whispers of wind, offering a bit of respite from the tropical heat. Interestingly, this month mirrors the calmness of October, both months experiencing the same light breeze, hinting at a seasonal shift as the city transitions into its cooler months. This easing of wind speeds continues a trend seen throughout the year, where April marks the year's lowest at 1.9 m/s and winds gradually pick up during the peak summer months, only to taper off as the rainy season approaches. Thus, September acts as a gentle bridge between the lively summer winds and the tranquil autumn whispers in Thailand's bustling capital.

Average September Wind Speed in Bangkok

The chart displays monthly wind speed patterns in Bangkok, with values for each month shown alongside September's data, which is highlighted for easy comparison. It illustrates the average wind speed, offering insights into how September's wind conditions compare to the rest of the year.
JanFebMarAprMayJunJulAugSepOctNovDec2.32.43.01.92.43.02.72.62.0 m/s2.02.22.6
Data source: Bangkok September wind data, generated using information from the Copernicus Climate Change Service.

How September Weather in Bangkok Compares to Other Months

Weather in Bangkok varies notably across the year, with each month offering distinct climate conditions. This page compares September’s weather to other months in Bangkok, focusing on differences in temperature, rainfall, humidity, and UV levels.

In September, Bangkok experiences much warmer temperatures with a minimum of 24°C (76°F), averaging 29°C (84°F), and peaking at 36°C (97°F). This month is characterized by significant precipitation, averaging 245 mm (9.6 in) over 24 rainy days, and high humidity levels at 87%. In contrast, January offers a cooler climate with temperatures ranging from a minimum of 16°C (61°F) to an average of 27°C (81°F) and a maximum of 35°C (94°F). Rainfall is minimal in January, totaling just 29 mm (1.1 in) across only 3 days, along with lower humidity at 59%. For more detailed information, see Bangkok weather in January.

September and February present contrasting weather patterns. In September, temperatures range from a minimum of 24°C (76°F) to a maximum of 36°C (97°F), with an average of 29°C (84°F). This month is characterized by significant rainfall, receiving 245 mm (9.6 in) spread over 24 days, making it quite humid with levels around 87%. In contrast, February features milder temperatures, with a minimum of 19°C (66°F) and a maximum of 35°C (96°F), averaging 28°C (82°F). Additionally, February is considerably drier, accumulating only 14 mm (0.5 in) of precipitation over just 3 days and maintaining a lower humidity level of 58%. For more details on the weather, visit Bangkok weather in February.

September and March present contrasting weather conditions. In September, temperatures range from a minimum of 24°C (76°F) to a maximum of 36°C (97°F), with an average of 29°C (84°F). This month is characterized by high humidity at 87% and significant rainfall, totaling 245 mm (9.6 in) over 24 days, making it one of the wettest months of the year. In contrast, March sees slightly cooler temperatures with a minimum of 22°C (72°F) and a maximum of 37°C (99°F), averaging 30°C (86°F). Additionally, March experiences much lower precipitation at just 44 mm (1.7 in) over 5 days and a reduced humidity level of 61%. For a detailed look at the weather specifics in March, check out Bangkok weather in March.

In comparison to September, April in Bangkok typically features slightly cooler evenings with a minimum temperature of 21°C (70°F) versus September's 24°C (76°F). While both months experience high humidity, September is notably more humid at 87%, compared to April's 70%. April also sees some of the highest temperatures of the year, with a maximum reaching 38°C (100°F), whereas September peaks at 36°C (97°F). Additionally, April has significantly lower precipitation, averaging 107 mm (4.2 in) over 12 days, compared to September's more substantial rainfall of 245 mm (9.6 in) over 24 days. For more information, see Bangkok weather in April.

In comparing the weather of September and May, we see that both months bring warm temperatures, but May tends to be slightly hotter with average highs reaching up to 40°C (103°F), compared to September’s maximum of 36°C (97°F). While September experiences a higher average humidity of 87% and significantly more rainfall with 245 mm (9.6 in) over 24 days, May remains drier with only 142 mm (5.6 in) and precipitation lasting 19 days. The overall warmer temperatures in May combined with lower humidity create a more intense heat, making it feel hotter than September, which, despite being humid, is slightly less oppressive. For more detailed information, you can check Bangkok weather in May.

When comparing the weather in September and June, we see some notable differences despite their proximity in the calendar. September experiences slightly lower temperatures, with a minimum of 24°C and an average of 29°C, compared to June's minimum of 25°C and average of 30°C. However, June typically boasts higher maximum temperatures, reaching up to 37°C, while September peaks at 36°C. Additionally, September is characterized by significantly higher precipitation, totaling 245 mm over 24 days, compared to June's 112 mm over 22 days, albeit with similar humidity levels of 87% and 85%, respectively. For more detailed insights about the weather during June, you can visit Bangkok weather in June.

In comparing the weather between September and July, we see some notable differences. September experiences a minimum temperature of 24°C (76°F) and an average of 29°C (84°F), with a maximum of 36°C (97°F). This month is marked by significantly higher rainfall, totaling 245 mm (9.6 in) over 24 days, resulting in a humid atmosphere at 87%. In contrast, July has slightly warmer temperatures, with a minimum of 25°C (78°F) and a maximum of 37°C (99°F), but brings only 159 mm (6.2 in) of precipitation over 26 days and a slightly lower humidity of 86%. For more details on July's weather, you can visit Bangkok weather in July.

In comparing the weather of September and August, we see notable differences in both temperature and precipitation. September experiences slightly lower minimum and maximum temperatures, with a range from 24°C (76°F) to 36°C (97°F), compared to August, which has temperatures ranging from 25°C (77°F) to 37°C (99°F). Both months have a similar average temperature of around 29°C (85°F), but September is the wetter month, recording 245 mm (9.6 in) of precipitation over 24 days, unlike August's 163 mm (6.4 in) over 23 days. Humidity levels remain high in both months, with September at 87% and August at 88%. For more detailed information, you can check the specifics for Bangkok weather in August.

In September, temperatures in Bangkok typically range from a minimum of 24°C (76°F) to a maximum of 36°C (97°F), with an average temperature of 29°C (84°F). The month is marked by significant precipitation, totaling 245 mm (9.6 in) over 24 days, accompanied by high humidity levels at 87%. Conversely, October sees slightly lower maximum temperatures, peaking at 35°C (96°F), while the average remains consistent at 29°C (84°F). Precipitation increases slightly to 250 mm (9.9 in) over a reduced number of rainy days (21), and humidity drops slightly to 83%. This suggests a marginally less oppressive feel to the weather in October compared to September. For more detailed information, you can refer to Bangkok weather in October.

In comparison to September, November experiences slightly cooler temperatures, with average highs of 35°C (95°F) compared to September's 36°C (97°F). September is also characterized by higher humidity at 87% and significantly more rainfall, with 245 mm (9.6 in) over 24 days, while November sees much less precipitation at 61 mm (2.4 in) across just 9 days. Overall, November provides a more pleasant climate, with lower humidity levels of 78%. For more detailed information, you can visit Bangkok weather in November.

September and December present contrasting weather conditions. In September, temperatures are higher, with a minimum of 24°C (76°F) and an average of 29°C (84°F), peaking at 36°C (97°F). The month is also characterized by significant rainfall, totaling 245 mm (9.6 in) over 24 days, and high humidity levels at 87%. In contrast, December features milder temperatures, with a minimum of 15°C (59°F) and an average of 27°C (80°F), reaching a maximum of 35°C (95°F). Precipitation in December is drastically lower, at just 24 mm (0.9 in) over only 2 days, along with a decrease in humidity to 70%. For more details on the seasonal changes, check out Bangkok weather in December.

Compare Bangkok's Climate with Cities Worldwide

Conclusion: What to Expect From September Weather in Bangkok

As September unfolds in Bangkok, the weather takes on a unique character, marked by sweltering temperatures and high humidity that can feel particularly intense. Unlike the preceding months, this period experiences frequent rain, with nearly every day seeing some level of precipitation, leading to a lush cityscape but also humidity levels soaring to 87%. The contrast is stark, as the warmth persists, with average temperatures hovering around a steamy 29°C. This combination of heat and moisture makes September one of the wetter months, setting it apart from the drier spells that precede and follow. For more insights on how Bangkok’s climate evolves throughout the year, explore Bangkok Climate.