September Weather in La Union, Mexico

Last updated: April 22, 2025

In September, La Union, Mexico experiences a warm climate, with maximum temperatures soaring to 37°C (100°F) and an average of 27°C (82°F). Nights bring a refreshing drop, with minimum temperatures around 18°C (64°F). While the month is dominated by high humidity levels (84%), it also witnesses considerable rainfall, accumulating 189 mm (7.4 in) over approximately 20 days. This blend of warmth and moisture creates a unique, vibrant atmosphere in La Union, making it a notable time for both locals and visitors alike.

September Temperature in La Union

In September, La Union begins to transition from the sweltering summer months, bringing a slight dip in temperatures while still offering warmth. The minimum temperature averages around 18°C (64°F), providing a comfortable start to the day, while the average climbs to a pleasant 27°C (82°F) during midday, perfect for enjoying outdoor activities. The peak temperatures can reach 37°C (100°F), reminiscent of the summer heat but with the promise of cooler evenings. As the month progresses, the heat gradually recedes, foreshadowing the milder temperatures of October. Overall, September strikes a balance between summer’s lingering warmth and the approaching autumn coolness, making it an enticing time to experience La Union's vibrant culture and stunning landscapes.

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.
JanFebMarAprMayJunJulAugSepOctNovDec677074798383838381787268
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

In September, La Union, Mexico experiences a significant increase in precipitation, with 189 mm (7.4 in) of rain falling over 20 days. This marks a continuation of the rainy season, building on August’s already generous 152 mm (6.0 in). The trend shows a steady climb in rainfall from the earliest months of the year, as May begins the gradual rise toward peak precipitation during the summer. June stands out with a remarkable 200 mm (7.9 in), followed closely by July and August. As the region transitions from summer to fall, September's abundant rainfall not only supports the local ecosystem but also signals the onset of cooler temperatures ahead.

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.
JanFebMarAprMayJunJulAugSepOctNovDec492740631392001231521891966318
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 noticeable rise in humidity, reaching 84%. This makes it a month where the air starts to feel notably warmer and more humid compared to the drier summer months of July and August, which recorded 72% and 74% respectively. As the year progresses, humidity levels tend to fluctuate, peaking in the winter months of January and October, at an impressive 88% and 92%. The transition into fall indicates a shift from the lighter summer air, hinting at a more moist atmosphere that characterizes the region's climate as the monsoon season approaches. Overall, while September sees a marked increase, it is part of a broader trend of elevated humidity levels leading into late autumn, creating a unique, tropical ambiance.

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.
JanFebMarAprMayJunJulAugSepOctNovDec89%86%83%80%82%79%72%74%84%92%91%91%
Data source: Humidity data for September generated using information from the Copernicus Climate Change Service.

September UV Index in La Union

In September, La Union, Mexico, experiences a UV Index of 12, maintaining an extreme exposure category that signals a serious risk for sun damage. This trend of elevated UV levels has persisted since March, peaking in the summer months with a maximum of 13 during June and July. With a consistent burn time of just 10 minutes, vacationers and locals alike should remain vigilant about sun protection. As we transition into the fall, October will slightly ease this intensity to a UV Index of 10, making it essential to still stay informed and protected. For further details on daily UV levels in La Union, 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.
JanFebMarAprMayJunJulAugSepOctNovDec710111212131312121087
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

As the summer draws to a close, September in La Union, Mexico offers an inviting mix of sunshine and warmth, boasting approximately 282 hours of glorious sunlight. This month showcases a gentle decline from the peak brightness of the summer months, particularly July's impressive 325 hours. Despite this reduction, September still offers plenty of sun-soaked days, making it a perfect time for outdoor adventures and relaxation. Moving from the intense heat of summer, visitors can enjoy fewer crowds while still relishing the vibrant atmosphere and stunning beaches, bridging the refreshing transition into fall with a generous dose of sunshine.

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.
JanFebMarAprMayJunJulAugSepOctNovDec169h205h264h270h314h304h325h318h282h269h240h231h
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 likelihood of sunny weather sees some ebb and flow throughout the year. September stands out with a 23% chance of sunshine, marking a slight dip from the vibrant summer months of July and August, which enjoy 35% and 44%, respectively. As the year transitions into autumn, the sun's presence becomes less reliable, with October improving slightly to 34%. The months leading up to September, particularly the spring, show higher percentages, with March peaking at 48%. This trend reflects a seasonal shift, where sunny days become less frequent as the rainy season approaches, making September a more variable month for sun-seekers in La Union.

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.
JanFebMarAprMayJunJulAugSepOctNovDec18%37%48%38%39%15%35%45%23%34%45%49%
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

In La Union, Mexico, September marks a subtle transition as daylight begins to wane, offering 12 hours of sunlight. This aligns with the latter part of a summer that sees the peak daylight duration at 13 hours in May through July. After basking in longer days, the sunlight gradually diminishes into the fall, with October dropping back to 11 hours. Interestingly, the pattern reveals a harmonious cycle, where daylight peaks in the summer months before receding gracefully into autumn, inviting residents and visitors alike to enjoy the balanced blend of warmth and twilight that September provides.

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.
JanFebMarAprMayJunJulAugSepOctNovDec11h11h 26m12h 2m12h 38m13h 8m13h 22m13h 14m12h 48m12h 13m11h 37m11h 6m10h 51m
Data source: La Union daylight hours, calculated by summing the hours between sunrise and sunset for each day.

September Winds in La Union

As summer transitions into fall in La Union, Mexico, September introduces a gentle breeze, with an average wind speed of 1.7 m/s (4 mph). This marks a slight dip compared to the preceding months, continuing a trend of diminishing wind speeds as the year progresses. While January through April showcase consistent gusts, peaking at 2.4 m/s (5 mph) in April, September’s softer winds reflect nature's gradual shift toward calmer conditions. As the vibrant energy of summer wanes, the refreshing autumn air invites leisurely strolls and peaceful days by the coast, offering a serene atmosphere that encapsulates the essence of the season.

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.
JanFebMarAprMayJunJulAugSepOctNovDec2.02.02.22.42.21.81.82.01.7 m/s1.81.91.8
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 patterns. In September, temperatures range from a minimum of 18°C (64°F) to a scorching maximum of 37°C (100°F), with an average of 27°C (82°F). This month also sees significant rainfall, totaling 189 mm (7.4 in) over roughly 20 days, accompanied by high humidity levels at 84%. In stark contrast, January features milder temperatures, with a minimum of 6°C (43°F) and a maximum of 34°C (94°F), averaging at 19°C (67°F). Precipitation is much lower in January, totaling just 49 mm (1.9 in) over about 7 days, while humidity remains slightly higher at 88%. For more details on January's climate, you can visit La Union weather in January.

In September, temperatures are generally warmer, with a minimum of 18°C (64°F) and an average of 27°C (82°F), peaking at a scorching 37°C (100°F). This month also sees significant rainfall, averaging 189 mm (7.4 in) over approximately 20 days, accompanied by high humidity at 84%. In contrast, February offers a cooler climate, with temperatures ranging from a low of 8°C (46°F) to a comfortable average of 21°C (70°F) and a maximum of 35°C (95°F). Precipitation is markedly lower at 27 mm (1.1 in) spread over just 7 days, while humidity remains high at 86%. For more details on February weather, visit La Union weather in February.

September and March present distinct weather patterns, highlighting the shift in seasons. In September, temperatures range from a low of 18°C (64°F) to a high of 37°C (100°F), with an average of 27°C (82°F). This month also experiences significant rainfall, with 189 mm (7.4 in) of precipitation over 20 days, contributing to a humid atmosphere at 84%. In contrast, March boasts a milder climate with temperatures varying from 10°C (51°F) to a maximum of 38°C (101°F), averaging at 23°C (74°F). Rainfall is considerably less, totaling only 40 mm (1.6 in) over 8 days, and humidity levels are slightly lower at 83%. For more detailed information, check the La Union weather in March.

In comparing the weather of September and April, September tends to be slightly warmer with average temperatures peaking at around 27°C (82°F) compared to April's average of 26°C (79°F). However, April can experience hotter days, with maximum temperatures reaching up to 41°C (107°F), which is significantly higher than September's maximum of 37°C (100°F). Additionally, September is characterized by higher precipitation, receiving about 189 mm (7.4 in) over approximately 20 days, while April sees much less rainfall, totaling around 63 mm (2.5 in) over just 8 days. Humidity levels are somewhat similar in both months, with September at 84% and April at 80%. For more detailed insights, you can refer to La Union weather in April.

September and May display some similarities in their warm temperatures, but also notable differences. In September, the average temperature is slightly lower at 27°C (82°F), with a maximum of 37°C (100°F), while May reaches a higher average of 28°C (83°F) and can peak at 40°C (105°F). September experiences more rainfall, with 189 mm (7.4 in) over 20 days compared to May's 138 mm (5.5 in) over 14 days. Humidity levels are comparable, with September at 84% and May at 82%. For a comprehensive overview of weather in May, check out La Union weather in May.

In September, the weather tends to be slightly cooler compared to June, with minimum temperatures dropping to 18°C (64°F) and average highs of 27°C (82°F), while June experiences a slightly warmer minimum of 20°C (69°F) and an average of 28°C (83°F). Although both months have similar average maximum temperatures, September boasts a peak of 37°C (100°F) compared to June’s 38°C (101°F). Rainfall is more prevalent in September, with 189 mm (7.4 in) over 20 days, while June sees a total of 200 mm (7.9 in) over just one additional day. Additionally, September is more humid at 84%, whereas June maintains a lower humidity level of 79%. For a detailed look at June weather, you can visit La Union weather in June.

September and July both exhibit warm temperatures, but September tends to be slightly cooler overall. In September, the minimum temperature starts at 18°C (64°F), with an average of 27°C (82°F) and can peak at 37°C (100°F). In contrast, July has a higher minimum of 21°C (69°F) and a slightly higher average temperature of 28°C (83°F), with a maximum of 37°C (98°F).

Additionally, September experiences more rainfall, with a total of 189 mm (7.4 in) compared to July's 123 mm (4.8 in), despite both months seeing precipitation on approximately 20 days. The humidity level in September is also higher at 84%, compared to July's 72%. For more details on July's weather, you can check La Union weather in July.

In comparing the weather patterns of September and August, September brings slightly cooler temperatures with an average of 27°C (82°F) and a maximum of 37°C (100°F), while August tends to be warmer, averaging 29°C (84°F) and peaking at 39°C (103°F). Humidity levels are notably higher in September at 84%, compared to August's 74%, which can make the warmer temperatures feel more oppressive. Additionally, September sees increased precipitation, with 189 mm (7.4 in) over 20 days, surpassing August's 152 mm (6.0 in) under similar rainfall conditions. For a detailed look at August weather specifics, you can visit La Union weather in August.

In comparing the weather of September and October, September tends to be slightly warmer, with average temperatures around 27°C (82°F), while October averages a cooler 25°C (78°F). Both months experience maximum temperatures peaking at 37°C (99°F to 100°F), but September has a higher minimum temperature of 18°C (64°F) compared to October's 15°C (60°F). Precipitation levels are fairly similar, with September receiving 189 mm (7.4 in) over 20 days and October slightly higher at 196 mm (7.7 in) but over just 17 days. Additionally, October experiences a higher humidity level at 92%, compared to September's 84%. For more detailed insights, you can check La Union weather in October.

In September, the weather is characterized by high temperatures, with a minimum of 18°C (64°F) and an average of 27°C (82°F), reaching peak highs of up to 37°C (100°F). The month is also marked by significant rainfall, averaging 189 mm (7.4 in) spread over 20 days, combined with high humidity levels of 84%. In contrast, November experiences much cooler temperatures, with a minimum of 4°C (39°F) and a more moderate average of 22°C (72°F), peaking at 32°C (90°F). Precipitation is notably lower in November, with only 63 mm (2.5 in) falling over 9 days, while humidity rises slightly to 91%. For more details on November's weather in La Union, you can visit La Union weather in November.

In September, the weather is characterized by higher temperatures, with averages around 27°C (82°F) and maximums reaching up to 37°C (100°F), coupled with significant precipitation of 189 mm (7.4 in) spread over 20 days, creating a humid atmosphere at 84%. In contrast, December experiences a cooler climate, where the average temperature drops to 20°C (69°F), with maximums of 33°C (92°F) and minimal precipitation of just 18 mm (0.7 in) over only 4 days. Interestingly, despite the lower temperatures, December's humidity rises slightly to 91%. For more detailed information on the December weather, 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 arrives in La Union, it ushers in a notable shift in weather patterns compared to the drier months of the year. With a maximum temperature soaring to 37°C (100°F), the heat is tempered by a significant rise in humidity, averaging around 84%, which contributes to the sultry atmosphere. This month is also characterized by its frequent rainfall, with precipitation occurring over 20 days and accumulating to about 189 mm (7.4 in), replenishing the lush surroundings and adding a refreshing twist to the tropical ambiance. In contrast to the more stable conditions encountered in the summer months, September's weather is marked by this vibrant blend of heat and moisture, making it a unique time to experience the captivating climate of the region. For a deeper understanding of what to expect throughout the year, check out La Union Climate.