September Weather in San Juan Vallarta, Mexico

Last updated: April 22, 2025

In San Juan Vallarta, Mexico, September ushers in a blend of warm and humid conditions, making it an ideal time for those who enjoy tropical climates. With maximum temperatures reaching around 29°C (85°F) and an average of 21°C (69°F), visitors can expect pleasant warmth. However, the month also brings the challenge of precipitation, as 314 mm (12.4 in) of rain falls over 26 days, resulting in a high humidity level of 82%. Travelers should prepare for a mix of sun and rain, ensuring an experience that embodies the vibrant essence of this coastal paradise.

September Temperature in San Juan Vallarta

In September, San Juan Vallarta enjoys a pleasant climate characterized by mild temperatures. The month starts with a minimum of 13°C (56°F), gradually rising to a comfortable average of 21°C (69°F), while daytime highs reach a maximum of 29°C (85°F). This transitional period marks a slight dip in temperature from the hotter summer months, making September an inviting time to explore the vibrant city and its stunning beaches. As the month unfolds, the temperatures remain relatively stable, offering a welcome balance of warmth without the oppressive heat, perfect for both relaxation and adventure under the sun.

September Weather in San Juan Vallarta: Daily Temperature Highs, Lows, and Averages

The chart illustrates September temperature patterns in San Juan Vallarta, showcasing daily minimum, maximum, and average temperatures. It highlights the typical range of temperatures throughout the month, providing insights into weather trends.
JanFebMarAprMayJunJulAugSepOctNovDec646771747471717169696764
Data source: Temperature data for San Juan Vallarta 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 San Juan Vallarta

September marks a peak in precipitation for San Juan Vallarta, with 314 mm (12.4 in) of rain falling over 26 days. This month often signals the height of the rainy season, as the intense summer rains culminate and prepare for a gradual retreat into the drier months ahead. Following a trend that sees rainfall steadily increase from January's merely 4 mm to September's substantial totals, the city experiences a noticeable shift between the arid winter months and the lush, vibrant summer foliage. As the wettest month of the year, September showcases the region's tropical character, setting the stage for a stunning transformation in the surrounding landscape as the rains nourish the flora.

September Precipitation Trends in San Juan Vallarta

The chart displays monthly precipitation patterns in San Juan Vallarta, 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.
JanFebMarAprMayJunJulAugSepOctNovDec561336132277198254315120364
Data source: Precipitation data for September generated using information from the Copernicus Climate Change Service.
Choose your preferred precipitation unit

September Humidity in San Juan Vallarta

As September unfolds in San Juan Vallarta, Mexico, the humidity begins to rise, reaching 82%—a notable increase from the summer months. While July and August enjoy a dip in humidity levels, September marks a transition back to the wetter conditions typical of the region. This month, with its lush greenery and vibrant atmosphere, provides a refreshing embrace, setting the stage for the even more humid months ahead, with October peaking at 91%. The trend emphasizes a gradual climb as the year progresses, showcasing Vallarta's tropical climate and the rich, humid tapestry that defines this beautiful coastal city.

September Average Humidity in San Juan Vallarta

This chart illustrates the average monthly humidity levels in San Juan Vallarta, with September's data highlighted for easy comparison. It shows the fluctuation in humidity throughout the year, allowing you to see how September's humidity levels compare to other months.
JanFebMarAprMayJunJulAugSepOctNovDec84%78%75%71%77%76%68%70%82%91%89%88%
Data source: Humidity data for September generated using information from the Copernicus Climate Change Service.

September UV Index in San Juan Vallarta

In September, San Juan Vallarta experiences an extreme UV Index of 14, reflecting a continuous trend of high solar exposure that starts in February and lasts through the summer months. This means that residents and visitors should be especially cautious, as the burn time is only 10 minutes. This pattern is consistent throughout the year with only slight fluctuations, peaking during the mid-year months. As the UV Index shifts slightly lower in October, it remains critical to protect your skin with sunscreen and protective clothing. Don’t forget to check out more about the UV index and safety tips at San Juan Vallarta UV Index.

Maximum UV Index Levels in San Juan Vallarta for September

The chart shows the monthly maximum UV Index (UVI) for San Juan Vallarta 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.
JanFebMarAprMayJunJulAugSepOctNovDec10121414141414141412109
Data source: San Juan Vallarta 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 San Juan Vallarta

As summer transitions into fall, September in San Juan Vallarta offers a delightful climate with 291 hours of sunshine. While this marks a slight dip from the sun-drenched peaks of the prior months—May's 332 hours stands as the sunniest—September still boasts a plentiful amount of light, showcasing the region's radiant charm. The month serves as a bridge between the intense warmth of summer, notably seen in July and August, and the more moderate days of autumn. This gradual decline in daylight hours hints at the approach of the cooler seasons, yet the lingering summer warmth continues to entice visitors to enjoy the beautiful beaches and vibrant local culture.

Monthly Sunshine Duration in San Juan Vallarta: September Highlighted

The September sunshine duration represents the total number of hours San Juan Vallarta 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.
JanFebMarAprMayJunJulAugSepOctNovDec244h278h320h320h332h303h329h316h291h304h294h298h
Data source: San Juan Vallarta September Sunshine duration data generated using information from the Copernicus Climate Change Service.

Chance of Sun in San Juan Vallarta During September

In San Juan Vallarta, September marks a transition into the rainy season, with a significantly lower chance of sunny weather compared to the earlier months. At just 19%, the likelihood of sunshine dwindles from the vibrant days of summer, making it one of the cloudiest months of the year. This trend starkly contrasts with the sunnier peaks in February (90%) and March (77%), highlighting that as summer fades, so too does the sun. Travelers seeking bright skies are advised to look towards October when the chances improve to 38%, or to plan their visits in the early months when the sun reigns supreme over this picturesque coastal paradise.

Percentage of Sunny Days in September in San Juan Vallarta

The chart illustrates the percentage of sunny days in San Juan Vallarta 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 San Juan Vallarta experiences clear skies throughout the year.
JanFebMarAprMayJunJulAugSepOctNovDec58%90%77%72%44%9%26%31%19%38%67%86%
Data source: San Juan Vallarta September chance of sun data, generated using information from the Copernicus Climate Change Service.

Daylight Hours in San Juan Vallarta in September

As September arrives in San Juan Vallarta, Mexico, daylight duration begins to settle into a balanced rhythm, offering 12 hours of sunlight each day. This reflects a slight decrease from the summer peak of 13 hours experienced in the preceding months of June, July, and August. The transition towards autumn is marked by a gentle tapering, leading into the shorter days of October, which also sees a return to 11 hours of daylight. Throughout the year, one can observe a predictable pattern: longer days prevail from late spring through summer, gradually giving way to the shorter days of the fall and winter months. This dynamic not only enhances the beauty of San Juan Vallarta but also invites visitors to embrace its vibrant atmosphere and captivating sunsets.

Average Daylight Hours in San Juan Vallarta for September

The chart illustrates the variation in daylight duration in San Juan Vallarta throughout the year, with September highlighted. It shows the monthly changes in daylight hours, calculated by summing the hours between sunrise and sunset.
JanFebMarAprMayJunJulAugSepOctNovDec11h 8m11h 31m12h 2m12h 34m13h13h 13m13h 6m12h 43m12h 12m11h 41m11h 14m11h
Data source: San Juan Vallarta daylight hours, calculated by summing the hours between sunrise and sunset for each day.

September Winds in San Juan Vallarta

As September unfolds in San Juan Vallarta, the gentle embrace of the wind continues to grace the coastal landscape, with an average speed of just 1.5 m/s (3 mph). This month features one of the calmest winds of the year, following a trend that sees wind activity decrease from the lively breezes of early spring. With averages peaking slightly at 2.2 m/s (5 mph) in the months of February and April, the late summer transition brings a serene stillness that invites relaxation and reflection. As temperatures remain warm, the soft September winds create a perfect backdrop for leisurely afternoons by the beach, effortlessly blending comfort and tranquility in this enchanting Mexican paradise.

Average September Wind Speed in San Juan Vallarta

The chart displays monthly wind speed patterns in San Juan Vallarta, 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.
JanFebMarAprMayJunJulAugSepOctNovDec2.02.22.02.21.81.51.61.51.5 m/s1.71.91.9
Data source: San Juan Vallarta September wind data, generated using information from the Copernicus Climate Change Service.

How September Weather in San Juan Vallarta Compares to Other Months

The weather in San Juan Vallarta changes throughout the year, offering a unique experience in each season. Below is a month-by-month comparison of September's weather with other months, highlighting differences in temperature, precipitation, and other key factors. Click on each section to discover seasonal trends in San Juan Vallarta and find detailed weather information for every month.

September and January present quite distinct weather patterns, highlighting the transition from late summer to winter. In September, temperatures range from a minimum of 13°C (56°F) to a maximum of 29°C (85°F), with a warm average of 21°C (69°F). This month also experiences significant rainfall, with 314 mm (12.4 in) expected over 26 days, contributing to an overall humidity level of 82%. In contrast, January is markedly cooler, featuring a minimum temperature of 5°C (41°F) and an average of 18°C (64°F), reaching a maximum of 30°C (86°F). However, this month sees minimal rain, accumulating just 4 mm (0.2 in) over 1 day, while humidity slightly rises to 84%. For a more detailed look at January weather patterns, visit San Juan Vallarta weather in January.

September and February showcase contrasting weather patterns. In September, temperatures range from a minimum of 13°C (56°F) to a maximum of 29°C (85°F), with an average of 21°C (69°F). This month is also characterized by high humidity at 82% and substantial rainfall, totaling 314 mm (12.4 in) over 26 days. In contrast, February enjoys milder conditions with temperatures dipping to a minimum of 7°C (45°F) and reaching a maximum of 31°C (88°F), averaging around 20°C (68°F). Notably, February experiences much lower precipitation, with only 6 mm (0.2 in) across just 2 days and humidity at a slightly lower 78%. For more detailed insights, check out San Juan Vallarta weather in February.

In comparing the weather between September and March, several notable differences emerge. September experiences a mild temperature range, with minimums around 13°C (56°F) and maximums reaching up to 29°C (85°F), accompanied by high humidity at 82%. This month also witnesses significant rainfall, with precipitation totaling 314 mm (12.4 in) over 26 days, creating a lush, yet damp atmosphere. In contrast, March offers warmer temperatures with a minimum of 9°C (48°F) and maximums soaring to 34°C (93°F), while maintaining a slightly lower humidity level of 75%. The precipitation drops dramatically to just 13 mm (0.5 in) over three days, resulting in a much drier climate. For more detailed information, you can explore San Juan Vallarta weather in March.

September and April present distinct weather profiles. In September, temperatures fluctuate between a minimum of 13°C (56°F) and a maximum of 29°C (85°F), with a humid average of 21°C (69°F). This month also experiences significant rainfall, with 314 mm (12.4 in) of precipitation over 26 days, resulting in high humidity levels at 82%. In contrast, April enjoys warmer conditions, featuring a higher average temperature of 23°C (74°F) and maximum highs reaching up to 34°C (93°F). Precipitation is minimal, totaling just 36 mm (1.4 in) across only 7 days, and with lower humidity at 70%. For more details, check out San Juan Vallarta weather in April.

In comparing the weather of September and May, September typically experiences cooler temperatures with a minimum of 13°C (56°F) and an average high of 29°C (85°F), while May boasts slightly warmer conditions, with a minimum of 14°C (57°F) and an average maximum reaching up to 35°C (95°F). Additionally, September is marked by significantly higher precipitation, totaling 314 mm (12.4 in) over 26 days, in contrast to May's more moderate rainfall of 131 mm (5.2 in) over just 17 days. Humidity levels are also higher in September at 82%, compared to 77% in May. For those interested in the specifics of May's climate patterns, you can find more detailed information here: San Juan Vallarta weather in May.

In comparing the weather between September and June, we see some notable differences. September typically experiences milder temperatures, with a minimum of 13°C (56°F) and a maximum of 29°C (85°F), averaging around 21°C (69°F). However, September is characterized by significantly higher precipitation, reaching 314 mm (12.4 in) over 26 days, coupled with an elevated humidity level of 82%. In contrast, June offers warmer weather with temperatures ranging from a minimum of 14°C (57°F) to a maximum of 35°C (94°F), averaging 22°C (71°F). While June also sees considerable rain, totaling 277 mm (10.9 in) across 24 days, it has a slightly lower humidity of 76%. For more detailed information about the weather during this month, you can check out San Juan Vallarta weather in June.

In comparing the weather between September and July, we observe notable differences in temperature and precipitation. September tends to be slightly warmer at night with a minimum of 13°C (56°F), compared to July’s minimum of 12°C (54°F). However, July boasts higher daytime temperatures, reaching up to a maximum of 32°C (91°F), while September peaks at 29°C (85°F). Precipitation levels are significantly higher in September, totaling 314 mm (12.4 in) over 26 days, in contrast to July's 198 mm (7.8 in) over 22 days. Furthermore, humidity is elevated in September at 82%, making it feel more muggy compared to the 68% humidity in July. For additional information, you can check out San Juan Vallarta weather in July.

In comparing the weather of September and August, we see some notable differences. September experiences a slightly cooler average temperature, with a minimum of 13°C (56°F) and a maximum of 29°C (85°F), whereas August sees higher temperatures, ranging from a minimum of 13°C (55°F) to a maximum of 32°C (90°F). Precipitation is significantly higher in September, totaling 314 mm (12.4 in) over 26 days compared to August's 254 mm (10.0 in) over 25 days, making September a wetter month. Additionally, humidity levels rise to 82% in September, up from 70% in August. For a more detailed look at August weather, you can visit San Juan Vallarta weather in August.

In September, the weather is characterized by mild temperatures, with lows around 13°C (56°F) and highs peaking at 29°C (85°F), along with significant precipitation of 314 mm (12.4 in) spread over 26 days, resulting in high humidity levels of 82%. In contrast, October brings cooler temperatures, with a minimum of 9°C (49°F) and an average of 20°C (69°F), while maximum temperatures rise slightly to 30°C (86°F). Notably, October experiences reduced rainfall of 120 mm (4.7 in) over 16 days, although humidity increases to 91%. For more detailed information, check San Juan Vallarta weather in October.

In September, the weather in San Juan Vallarta is characterized by warmer temperatures, with an average of 21°C (69°F) and maximum highs reaching up to 29°C (85°F). However, this month also sees significant rainfall, accumulating to 314 mm (12.4 in) over 26 days, and the humidity levels remain high at 82%.

In contrast, November brings cooler temperatures with an average of 19°C (67°F) and occasional highs of 30°C (86°F). The precipitation dramatically decreases to just 36 mm (1.4 in) across 5 days, although humidity rises slightly to 89%. For a more detailed look at the weather conditions during this month, check out San Juan Vallarta weather in November.

In September, the weather in San Juan Vallarta is characterized by warm temperatures, with an average of 21°C (69°F), and can reach highs of 29°C (85°F). However, this month also sees significant rainfall, with 314 mm (12.4 in) of precipitation spread over 26 days, contributing to a high humidity level of 82%. In contrast, December experiences cooler temperatures, with a minimum of 5°C (41°F) and an average of 18°C (65°F), though it can still peak at 29°C (85°F). Notably, December boasts extremely low precipitation, with just 4 mm (0.1 in) and no rainy days at all, leading to a slightly higher humidity of 88%. For more details, you can check San Juan Vallarta weather in December.

Compare San Juan Vallarta's Climate with Cities Worldwide

Conclusion: What to Expect From September Weather in San Juan Vallarta

As September unfolds in San Juan Vallarta, it brings a unique blend of warm temperatures and increased rainfall, setting it apart from other months. With humidity hovering around an intense 82%, the atmosphere feels more tropical, making for a lush environment. However, this month is characterized by frequent rainfall, with nearly every day experiencing some precipitation, contributing to a total of 314 mm throughout the month. While visitors can still enjoy warm days, the added moisture makes the evenings cooler and offers a refreshing respite from summer's heat. Embrace this vibrant season and discover more about the area's unique weather patterns by exploring the San Juan Vallarta Climate.