Last updated: August 27, 2025
September in Phra Nakhon Si Ayutthaya, Thailand presents a tropical climate characterized by high humidity levels averaging 88%. Temperatures can soar to a maximum of 37°C (98°F), while the average hovers around a comfortable 29°C (84°F). The month is marked by substantial rainfall, with a total precipitation of 279 mm (11.0 in) over approximately 25 days, making it one of the wetter periods of the year. Visitors can expect lush greenery along with warm, occasional downpours, creating a uniquely vibrant atmosphere in this historic city.
In September, Phra Nakhon Si Ayutthaya experiences a warm subtropical climate, with temperatures that continue the trend of late summer heat. The minimum temperature hovers around 24°C (76°F), while the average settles at 29°C (84°F), providing a comfortable yet tropical ambiance. The maximum temperatures can reach up to 37°C (98°F), marking a slight decrease from the peak summer months of April and May, when temperatures soared above 40°C (104°F). As the month progresses, there's a gradual drop in intensity, hinting at the approach of the cooler season. Overall, September strikes a balance, with warm days and mild nights, making it a vibrant time to explore this historically rich destination.
September marks a significant shift in rainfall for Phra Nakhon Si Ayutthaya, Thailand, as it receives 279 mm (11.0 in) of precipitation, making it the wettest month of the year. This surge in rainfall accompanies an increase in rainy days, with 25 days of showers, reflecting the peak of the monsoon season. The progression of precipitation from the early year shows a gradual climb, with amounts ranging from 17 mm in January to 194 mm in August, leading up to this dramatic September peak. This consistent rise highlights September as a crucial time for water replenishment in the region, setting the stage for the slightly reduced but still substantial rainfall in October.
As the summer months bloom into September in Phra Nakhon Si Ayutthaya, Thailand, the landscape is enveloped in a palpable humidity, peaking at a notable 88%. This increase continues the trend observed since June, where humidity levels have soared, with August already setting a high bar at 85%. The transition from the drier months of January through April, which hovered between 41% and 51%, dramatically shifts as the wet season progresses. By the time September arrives, the air is thick with moisture, which perfectly encapsulates the tropical essence of the region. Following September, humidity tends to gradually decrease, signaling a slow return to a more comfortable climate as October approaches with 79%. The overall pattern highlights how the months leading into and during the monsoon season significantly influence the area's climate, transforming Phra Nakhon Si Ayutthaya into a lush, verdant haven.
In September, Phra Nakhon Si Ayutthaya experiences a UV Index of 13, categorizing this month as extreme and indicative of the ongoing high sun exposure prevalent throughout the rainy season. With a burn time of just 10 minutes, it's crucial to take precautions when spending time outdoors. Following a consistently intense summer, September continues the trend of elevated UV levels typical from February through August, where indices regularly peak at 14. As the year progresses into October, there is a slight decrease to an index of 12, yet the overall pattern showcases the region's propensity for extreme UV conditions. For anyone planning outdoor activities, understanding these UV levels is essential for protection. For more information, check out the Phra Nakhon Si Ayutthaya UV Index.
UV Risk Categories
As summer gracefully transitions into autumn, September in Phra Nakhon Si Ayutthaya reveals a mild decline in sunlight, with 268 hours of radiant exposure, compared to the summer peak of 333 hours in March. This month, while still basking in warmth, hints at the impending cooler days, aligning with a gradual downward trend in sunshine hours from a summer high. The gentle subsiding of sunlight continues into October, which offers 287 hours, ushering the historic city into a beautiful autumn ambiance. Visitors can savor the charm of Ayutthaya’s ancient ruins basking in the golden light, making September an enchanting time to explore, even as the sun subtly prepares to rest for the year.
When considering the likelihood of sunny weather in September in Phra Nakhon Si Ayutthaya, it's important to note a significant trend: the chances of clear skies dramatically drop as the year progresses. With only a 10% chance of sunshine in September, the month follows a pattern of increasing cloudiness that starts in mid-year. This contrasts sharply with the brighter months of January and February, where the probability of sunny days peaks at 59% and 79%, respectively. As the region transitions into the rainy season, the sun becomes less frequent, making September one of the least favorable months for sun seekers in Thailand.
In Phra Nakhon Si Ayutthaya, Thailand, September marks a continuation of the summer-like consistency in daylight duration, as the region enjoys a generous 12 hours of sunlight. From March through September, daylight remains stable at this length, reflecting the tropical climate's minimal variations across these months. Notably, this period of extended daylight offers a vibrant atmosphere perfect for exploring the rich cultural heritage and stunning landscapes. As the year transitions into October, daylight begins to wane, dipping back to 11 hours, signaling the gradual shift toward the cooler months and a return to shorter days. This pattern showcases the relatively consistent lighting throughout much of the year, providing a dependable backdrop for both residents and visitors alike.
As September unfolds in Phra Nakhon Si Ayutthaya, the weather begins to shift subtly, marked by an average wind speed of 2.0 m/s (4 mph). This gentle breeze is a slight dip from the summer months, indicating a transition toward the cooler, drier air of the approaching autumn. While June boasts the strongest gusts, averaging 3.0 m/s (7 mph), winds in September evoke a sense of tranquility, reminiscent of the peaceful days of April with its calmness. Throughout the year, the wind speeds fluctuate, peaking in mid-year before settling into the ease of fall. This gentle September breeze enhances the historic ambiance of Ayutthaya, echoing the whispers of ancient tales carried through the ages.
Weather in Phra Nakhon Si Ayutthaya varies notably across the year, with each month offering distinct climate conditions. This page compares September’s weather to other months in Phra Nakhon Si Ayutthaya, focusing on differences in temperature, rainfall, humidity, and UV levels.
In September, the weather is characterized by high temperatures, with a minimum of 24°C (76°F) and an average of 29°C (84°F), reaching up to a scorching maximum of 37°C (98°F). This month also sees significant rainfall, with 279 mm (11.0 in) spread over 25 days and high humidity at 88%, making it feel quite oppressive. In contrast, January offers a more temperate climate, with minimum temperatures around 16°C (61°F) and an average of 27°C (81°F), peaking at 36°C (96°F). Precipitation drops dramatically to just 17 mm (0.7 in) over 3 days and humidity levels decrease to a more comfortable 50%, making January a much drier and cooler month overall. For more detailed information, you can check Phra Nakhon Si Ayutthaya weather in January.
September and February present contrasting weather conditions in Phra Nakhon Si Ayutthaya. September experiences significantly warmer temperatures, with average highs reaching up to 37°C (98°F) and high humidity levels at 88%. This month also sees substantial rainfall, totaling 279 mm (11.0 in) over approximately 25 days, creating a rather damp environment. In contrast, February brings some relief with milder temperatures, where the minimum dips to 18°C (65°F) and the average remains comfortable at 28°C (83°F), while still peaking at 37°C (98°F). The precipitation during this month is minimal, averaging only 12 mm (0.5 in) across just 3 days, and the humidity drops significantly to 47%, resulting in a much drier atmosphere. For a more detailed look at February's climate, visit Phra Nakhon Si Ayutthaya weather in February.
September and March present markedly different weather conditions. In September, temperatures range from a minimum of 24°C (76°F) to a maximum of 37°C (98°F), with a high average of 29°C (84°F). This month sees substantial rainfall, accumulating to 279 mm (11.0 in) over 25 days, and the humidity remains high at 88%. In contrast, March offers slightly warmer conditions, with temperatures varying from 23°C (73°F) to 39°C (102°F) and an average of 30°C (86°F). Rainfall is significantly lower, with only 47 mm (1.8 in) over just 5 days, contributing to a much drier atmosphere with a humidity level of 41%. For more detailed weather information, check out Phra Nakhon Si Ayutthaya weather in March.
In comparing the weather between September and April, there are notable differences in temperature, precipitation, and humidity. September typically features a minimum temperature of 24°C (76°F) and an average of 29°C (84°F), with maximums reaching up to 37°C (98°F). This month experiences considerable rainfall, with 279 mm (11.0 in) over approximately 25 days, contributing to a high humidity level of 88%. In contrast, April has a slightly higher minimum temperature of 20°C (68°F) and an average of 31°C (87°F), peaking at 40°C (104°F). However, it receives significantly less rainfall, totaling 100 mm (4.0 in) across 15 days and a much lower humidity level at 51%. This makes April feel drier and hotter overall. For more detailed weather information, you can refer to Phra Nakhon Si Ayutthaya weather in April.
September and May exhibit notable differences in weather patterns. In September, temperatures range from a minimum of 24°C (76°F) to a maximum of 37°C (98°F), with an average temperature of 29°C (84°F). This month experiences significant rainfall, totaling 279 mm (11.0 in) over 25 days, accompanied by high humidity levels at 88%. In contrast, May boasts slightly warmer temperatures, with a minimum of 23°C (74°F), an average of 30°C (87°F), and a maximum reaching 40°C (104°F). Rainfall is less frequent in May, amounting to 166 mm (6.5 in) over 21 days, along with lower humidity levels at 76%. For a more detailed look at May's weather, you can check Phra Nakhon Si Ayutthaya weather in May.
In comparing the weather of September and June, we can see some noteworthy differences. September features slightly cooler average temperatures, with a minimum of 24°C (76°F) and an average of 29°C (84°F), while June boasts a minimum of 25°C (77°F) and an average of 30°C (86°F). However, June experiences higher maximum temperatures, reaching up to 39°C (102°F), compared to September's peak of 37°C (98°F).
Precipitation also varies significantly between the two months; September sees much more rainfall, with 279 mm (11.0 in) spanning 25 days, compared to June's 135 mm (5.3 in) over 22 days. Additionally, humidity levels are higher in September at 88%, while June has a slightly lower humidity level of 83%. For a closer look at the weather specifics, you can visit Phra Nakhon Si Ayutthaya weather in June.
When comparing the weather in September and July, both months exhibit high temperatures and considerable humidity, but with some notable differences. In September, temperatures range from a minimum of 24°C (76°F) to a maximum of 37°C (98°F), maintaining an average of 29°C (84°F). The month experiences more precipitation, totaling 279 mm (11.0 in) over 25 days, resulting in a higher humidity level of 88%. In contrast, July sees slightly warmer temperatures, with a minimum of 25°C (77°F) and a maximum of 38°C (101°F), averaging 29°C (85°F). However, it has less rainfall, with 179 mm (7.1 in) recorded over 26 days and a humidity level of 80%. For more specific details about July weather, check out Phra Nakhon Si Ayutthaya weather in July.
In comparing the weather between September and August, we find that both months exhibit similar minimum temperatures at 24°C (76°F) and average temperatures around 29°C. However, August tends to be slightly warmer with a maximum temperature of 38°C (101°F) compared to September's peak of 37°C (98°F). Both months experience significant precipitation, but September sees a notable increase with 279 mm (11.0 in) of rainfall over 25 days, compared to August's 194 mm (7.6 in). Additionally, humidity levels are marginally higher in September at 88%, compared to August's 85%. For more detailed information on the weather during August, you can check this link: Phra Nakhon Si Ayutthaya weather in August.
In September, the weather remains quite warm with minimum temperatures around 24°C (76°F) and maximums peaking at 37°C (98°F). The month witnesses heavy rainfall, amassing 279 mm (11.0 in) over 25 days, contributing to a high humidity level of 88%. In contrast, October experiences slightly cooler nights with a minimum temperature of 22°C (71°F), while daily highs remain the same at 37°C (99°F). Rainfall decreases to 212 mm (8.4 in) across 19 days, and the humidity drops to a more comfortable 79%. For more detailed information, you can check Phra Nakhon Si Ayutthaya weather in October.
In September, the weather is notably warmer and more humid, with temperatures ranging from a minimum of 24°C (76°F) to a maximum of 37°C (98°F). This month experiences significant rainfall, with a total of 279 mm (11.0 in) spread across 25 days, leading to a humidity level of 88%. In contrast, November brings a slight decrease in temperatures, with minimums around 21°C (70°F) and maximums reaching 36°C (97°F). The precipitation drops significantly to 50 mm (2.0 in) over just 8 days, and the humidity also decreases to 68%. This shift results in a more comfortable and drier climate during November, making it a favorable time for outdoor activities. For more detailed information, check out Phra Nakhon Si Ayutthaya weather in November.
In September, the weather is characterized by higher temperatures and significantly more humidity, with minimum temperatures around 24°C (76°F), an average of 29°C (84°F), and peak temperatures reaching 37°C (98°F). This month also sees substantial rainfall, with 279 mm (11.0 in) of precipitation spread over 25 days, resulting in very humid conditions (88%).
Contrastingly, December brings a noticeable relief from the sweltering heat, with cooler minimum temperatures of 15°C (60°F) and an average of 27°C (81°F). The maximum temperature hovers around 36°C (97°F), but the weather is much drier, receiving only 18 mm (0.7 in) of precipitation over just 3 days and humidity levels dropping to 59%. For a closer look at December weather specifics, visit Phra Nakhon Si Ayutthaya weather in December.
As September unfolds in Phra Nakhon Si Ayutthaya, it marks a significant shift in weather patterns compared to other months. With notably high humidity levels and frequent rains, this month experiences a substantial increase in precipitation, often leading to lush, vibrant landscapes. The warm temperatures, peaking at 37°C, can feel even more intense due to the moisture-laden air, making it essential for visitors to prepare for both heat and sudden downpours. For those looking to understand seasonal trends, this month serves as a reminder that the climate here is dynamic and ever-changing. For more detailed insights, explore the complete overview at Phra Nakhon Si Ayutthaya Climate.