September Weather in La Union, Mexico

Last updated: April 22, 2025

In September, La Union, Mexico, basks in warm temperatures, with maximums reaching 40°C (104°F) and an average of 30°C (86°F). Nights cool down to a comfortable minimum of 22°C (72°F), providing a pleasant respite from the daytime heat. This month also brings a considerable amount of moisture, with 77 mm (3.0 in) of precipitation spread over 10 days, contributing to a high humidity level of 82%. Visitors should be prepared for both sun-soaked days and occasional rain, making September a vibrant yet humid month in this coastal paradise.

September Temperature in La Union

In September, La Union, Mexico experiences a tropical heat surge, with minimum temperatures hovering around a comfortable 22°C (72°F) and average highs reaching a sizzling 30°C (86°F). As the month progresses, the mercury can climb to a scorching 40°C (104°F), marking it as one of the hottest times of the year. This trend of increasing temperatures from the previous summer months reflects the peak of the warm season, creating a vibrant atmosphere perfect for beachgoers and outdoor enthusiasts. With warm evenings ideal for relaxation, September showcases La Union's balmy tropical climate, making it a prime time for visitors to soak in the sun and revel in the region's natural beauty.

September Weather in La Union: Daily Temperature Highs, Lows, and Averages

The chart illustrates September temperature patterns in La Union, showcasing daily minimum, maximum, and average temperatures. It highlights the typical range of temperatures throughout the month, providing insights into weather trends.
JanFebMarAprMayJunJulAugSepOctNovDec646568737884878886837466
Data source: Temperature data for La Union generated using information from the Copernicus Climate Change Service.
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The average of daily temperatures (24 hours) calculated across all days in the month.

September Precipitation in La Union

September marks a significant shift in precipitation patterns for La Union, Mexico, with rainfall reaching 77 mm (3.0 in) over 10 days. This increase follows a gradually rising trend from the dry spring months, where April and May recorded no precipitation, to the wettest summer months of July and August. As the rainy season peaks, September’s showers contribute to lush landscapes and replenished water sources, serving as a precursor to the tapering rainfall of October and the following months. The heightened rainfall underscores the region’s transition from aridity to a vibrant, rejuvenating wet season, illustrating a clear progression in La Union's climate patterns.

September Precipitation Trends in La Union

The chart displays monthly precipitation patterns in La Union, 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.
JanFebMarAprMayJunJulAugSepOctNovDec13950018367377202816
Data source: Precipitation data for September generated using information from the Copernicus Climate Change Service.
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September Humidity in La Union

In September, La Union, Mexico, experiences a surge in humidity, reaching 82%, marking one of the highest levels of the year. This increase follows a pattern established in the preceding months, where humidity gradually climbed from a low of 47% in May to 81% in August. The transition into September not only ushers in the rainy season but also signals a noticeable shift from the drier spring months. Surprisingly, while October shows a slight dip to 78%, the overall trend reflects a humid environment that characterizes the region's late-summer and autumn months, showcasing the tropical climate's vibrancy and the lush landscapes that result from such moisture.

September Average Humidity in La Union

This chart illustrates the average monthly humidity levels in La Union, 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.
JanFebMarAprMayJunJulAugSepOctNovDec75%67%60%51%47%50%70%82%82%78%78%81%
Data source: Humidity data for September generated using information from the Copernicus Climate Change Service.

September UV Index in La Union

As September rolls into La Union, Mexico, residents and visitors alike should be prepared for an extreme UV Index of 12, which means a burn time of just 10 minutes before needing protection. This marks the continuation of a trend seen from April through August, where the UV levels also peaked at 12. Such consistently high levels signal that sun safety is paramount during these months, emphasizing the importance of protective measures like sunscreen and hats. As the year transitions, the UV Index will gradually drop to 10 in October, still indicating very high exposure risks. For more detailed information on UV trends throughout the year, check out La Union UV Index.

Maximum UV Index Levels in La Union for September

The chart shows the monthly maximum UV Index (UVI) for La Union 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.
JanFebMarAprMayJunJulAugSepOctNovDec68101212121212121075
Data source: La Union 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 La Union

September in La Union, Mexico, wraps up the summer with a radiant 298 hours of sunshine, a charming transition from the warmer months. Following the peak of 364 hours in May, the sunlight begins to taper off, yet remains robust through the fall. This month, while less sun-drenched than the height of summer, still outshines the dark winter months ahead. As daylight gracefully dwindles, it hints at the approaching transition into a cooler landscape, making September a delightful time to enjoy the lingering warmth and vibrant atmosphere of this coastal paradise.

Monthly Sunshine Duration in La Union: September Highlighted

The September sunshine duration represents the total number of hours La Union 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.
JanFebMarAprMayJunJulAugSepOctNovDec220h255h299h325h364h356h341h326h298h303h266h263h
Data source: La Union September Sunshine duration data generated using information from the Copernicus Climate Change Service.

Chance of Sun in La Union During September

In La Union, Mexico, the month of September brings a 60% chance of sunny weather, reflecting a slight dip in sunshine compared to the peak months of May and October, which boast probabilities of 79% and 84%, respectively. This mid-range likelihood suggests September acts as a transitional period, bridging the intense sunshine of summer with the clearer skies of fall. Following the notably lower chances in July and August, September provides a welcomed opportunity for outdoor activities, making it a viable option for those seeking a blend of warmth and pleasant weather. As the month progresses, one can expect a gradual shift toward more consistent sunny days leading into October.

Percentage of Sunny Days in September in La Union

The chart illustrates the percentage of sunny days in La Union 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 La Union experiences clear skies throughout the year.
JanFebMarAprMayJunJulAugSepOctNovDec70%58%67%72%79%70%45%44%60%84%69%53%
Data source: La Union September chance of sun data, generated using information from the Copernicus Climate Change Service.

Daylight Hours in La Union in September

As summer transitions into autumn, September in La Union, Mexico, brings a gentle shift in daylight duration, offering approximately 12 hours of sunlight. This month marks a gradual decline from the peak 13 hours seen during the summer months of June, July, and August. Following September, daylight continues to wane, with October and November featuring 11 and 10 hours, respectively. This trend reflects the region's distinct seasonal shifts, where the longer, sun-drenched days of summer give way to the cooler, shorter days of fall, creating a beautiful interplay of light and shadow that signifies the changing seasons.

Average Daylight Hours in La Union for September

The chart illustrates the variation in daylight duration in La Union throughout the year, with September highlighted. It shows the monthly changes in daylight hours, calculated by summing the hours between sunrise and sunset.
JanFebMarAprMayJunJulAugSepOctNovDec10h 39m11h 15m12h 1m12h 48m13h 27m13h 46m13h 36m13h 1m12h 16m11h 29m10h 48m10h 28m
Data source: La Union daylight hours, calculated by summing the hours between sunrise and sunset for each day.

September Winds in La Union

As September rolls into La Union, Mexico, the gentle breeze begins to soften, bringing an average wind speed of 2.5 m/s (6 mph). This subtle change marks the onset of a transitional phase, as the summer months recede and a cooler ambiance settles in. Throughout the summer, from June to August, winds typically peak at 3.4 m/s (8 mph) in June, creating vibrant conditions perfect for outdoor festivities. However, as we move into fall, wind speeds tend to taper off, aligning September with the lighter conditions seen in January and February. This trend reflects the region’s cyclical rhythm, where each month plays its part in crafting the unique climate tapestry of La Union. As September’s softness embraces the shores, it invites a moment of reflection and tranquility amidst the lingering warmth of summer.

Average September Wind Speed in La Union

The chart displays monthly wind speed patterns in La Union, 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.
JanFebMarAprMayJunJulAugSepOctNovDec2.62.73.23.13.03.42.82.62.5 m/s2.82.42.6
Data source: La Union September wind data, generated using information from the Copernicus Climate Change Service.

How September Weather in La Union Compares to Other Months

The weather in La Union 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 La Union and find detailed weather information for every month.

September and January present contrasting weather experiences. In September, temperatures soar with a minimum of 22°C (72°F) and an average reaching 30°C (86°F), often peaking at a scorching 40°C (104°F). This month also sees significant humidity at 82% and about 77 mm (3.0 in) of precipitation over approximately 10 days, creating a muggy atmosphere. In stark contrast, January features much cooler conditions, with minimum temperatures dropping to 7°C (45°F) and an average of 18°C (64°F), peaking at a more moderate 30°C (86°F). This month boasts significantly less rainfall, with only 13 mm (0.5 in) over about 1 day, and lower humidity levels at 74%. For more details, you can visit La Union weather in January.

September and February present strikingly different weather conditions. In September, temperatures soar with a minimum of 22°C (72°F) and can reach a sweltering maximum of 40°C (104°F), paired with high humidity at 82% and average precipitation of 77 mm (3.0 in) over about 10 days. In contrast, February offers much cooler temperatures, with a minimum of 7°C (45°F) and an average of 18°C (65°F), peaking at 30°C (86°F). It experiences significantly less rainfall, with just 9 mm (0.4 in) and only about 1 day of precipitation, along with lower humidity at 67%. For a closer look at February weather, visit La Union weather in February.

September and March showcase contrasting weather patterns. September typically experiences higher temperatures, with minimums around 22°C (72°F) and maximums reaching up to 40°C (104°F), averaging a sweltering 30°C (86°F). The month is also characterized by significant humidity at 82% and considerable precipitation, averaging 77 mm (3.0 in) over about 10 days. In contrast, March is much cooler, with temperatures ranging from a low of 9°C (49°F) to a high of 32°C (90°F), and an average of 20°C (68°F). The month enjoys mild weather, featuring only 5 mm (0.2 in) of precipitation over just a single day and a lower humidity level of 60%. For more specific weather details in March, you can visit La Union weather in March.

September and April present striking contrasts in weather patterns. In September, the temperatures soar with a minimum of 22°C (72°F) and an average high of 30°C (86°F), reaching up to a sweltering 40°C (104°F). This period is also characterized by significant humidity at 82% and frequent rain, accumulating 77 mm (3.0 in) over about 10 days. In stark contrast, April enjoys milder weather with a minimum temperature of 13°C (55°F) and an average of 23°C (73°F), peaking at 34°C (94°F). This month showcases dry conditions, with no recorded rainfall and a much lower humidity level of 51%. For a closer look at the April climate specifics, you can visit La Union weather in April.

September and May exhibit contrasting weather patterns in terms of temperature, precipitation, and humidity. In September, temperatures range from a minimum of 22°C (72°F) to a scorching maximum of 40°C (104°F), with an average of 30°C (86°F). This month also experiences significant rainfall, with 77 mm (3.0 in) falling over ten days, resulting in a high humidity level of 82%. In contrast, May offers milder conditions, with a temperature range from 16°C (61°F) to a maximum of 38°C (100°F) and a comfortable average of 25°C (78°F). Notably, May boasts no rainfall and low humidity at 47%, making it a much drier and more pleasant month overall. For more details, check out La Union weather in May.

In comparing the weather of September and June, September tends to be warmer overall, with average temperatures reaching up to 30°C (86°F) and maximum temperatures soaring to 40°C (104°F). This month also experiences significantly higher humidity at 82%, contributing to the discomfort during the peak heat. In contrast, June, though slightly cooler with an average temperature of 29°C (84°F) and a maximum of 38°C (100°F), boasts much lower humidity at 50% and virtually no precipitation, with only 18 mm (0.7 in) over the month. For more specific details about June weather, you can check La Union weather in June.

When comparing the weather in September and July, September tends to be slightly cooler but more humid. In September, temperatures range from a minimum of 22°C (72°F) to a maximum of 40°C (104°F), with an average of 30°C (86°F). The month sees higher precipitation levels, receiving about 77 mm (3.0 in) over approximately 10 days, resulting in a humidity level of 82%. In contrast, July has a minimum temperature of 24°C (76°F) and a maximum of 38°C (100°F), averaging 31°C (88°F). It experiences less rainfall, with only 36 mm (1.4 in) over about 5 days, and a lower humidity of 70%. For more detailed insights, check out La Union weather in July.

In September, temperatures show a slight decrease compared to August, with minimums dropping from 25°C (77°F) to 22°C (72°F) and maximums remaining relatively stable at 40°C (104°F) in September versus 39°C (102°F) in August. The average temperature in September is 30°C (86°F), just slightly lower than August's average of 31°C (88°F). Precipitation increases marginally in September to 77 mm (3.0 in) across 10 days, compared to 73 mm (2.9 in) over 9 days in August. Humidity remains high in both months, with September at 82% and August at 81%. For a more detailed look at the weather conditions in August, check out La Union weather in August.

September weather tends to be hotter and more humid compared to October, with average temperatures reaching 30°C (86°F) and maximums soaring up to 40°C (104°F). The month experiences significant rainfall, with 77 mm (3.0 in) of precipitation over approximately 10 days, resulting in an elevated humidity level of 82%.

In contrast, October brings a noticeable decrease in both temperature and humidity, with average temperatures around 28°C (83°F) and maximums peaking at 39°C (102°F). Moreover, October is significantly drier, receiving only 20 mm (0.8 in) of rain over just 2 days, bringing humidity down to 78%.

For more detailed information on October weather, you can check La Union weather in October.

In September, the weather is significantly warmer, with average temperatures hovering around 30°C (86°F) and daily highs reaching up to 40°C (104°F). The month also experiences substantial rainfall, totaling 77 mm (3.0 in) over approximately 10 days, coupled with high humidity levels of 82%. In contrast, November brings a noticeable drop in temperatures, with averages around 24°C (75°F) and maximums capping at 36°C (97°F). Additionally, November sees much less precipitation, totaling only 28 mm (1.1 in) over just 2 days, and a slight decrease in humidity to 78%. For more detailed insights, you can check out La Union weather in November.

September and December weather in La Union exhibit a striking contrast, reflecting the transition from summer to winter. In September, temperatures range from a minimum of 22°C (72°F) to a scorching maximum of 40°C (104°F), with an average of 30°C (86°F). This month also experiences substantial precipitation, totaling 77 mm (3.0 in) over approximately 10 days, accompanied by relatively high humidity at 82%. In stark comparison, December sees a significant drop in temperatures, with a minimum of 8°C (47°F), an average of 19°C (66°F), and a maximum of 30°C (87°F). Precipitation decreases dramatically to just 16 mm (0.6 in) over about 2 days, while humidity remains relatively stable at 80%. For more detailed information, you can visit La Union weather in December.

Compare La Union's Climate with Cities Worldwide

Conclusion: What to Expect From September Weather in La Union

As September unfolds in La Union, the weather presents a unique contrast to the scorching summer months. With average temperatures hovering around a pleasant 30°C (86°F), the month provides a welcome respite from the peak heat of summer, though it can still reach highs of 40°C (104°F) on warmer days. The increased humidity, at 82%, along with occasional rainfall—recording 77 mm over about 10 days—fosters a more tropical atmosphere. This seasonal shift hints at the transition to autumn, offering a refreshing perspective on La Union’s climate. To explore more about the regional weather patterns, visit La Union Climate.