September Weather in Monterrey, Mexico

Last updated: April 22, 2025

September in Monterrey, Mexico showcases a transition into the fall season, characterized by a maximum temperature of 25°C (77°F) and an average temperature of 17°C (62°F). As autumn approaches, daytime warmth is tempered by cooler evenings, with minimum temperatures dropping to 7°C (45°F). This month also brings significant rainfall, totaling 251 mm (9.9 in) across approximately 24 days, leading to a notably humid environment with levels reaching 86%. Visitors to Monterrey should prepare for a mix of warm and wet days, making proper attire essential for enjoying this vibrant city during its rainy season.

September Temperature in Monterrey

As September rolls into Monterrey, the city enjoys a pleasant transition into autumn with temperatures that hover around a mild average of 17°C (62°F). The month begins with minimums at 7°C (45°F), nudging slightly down to a comfortable max of 25°C (77°F), making it one of the year's most agreeable periods. Compared to the sweltering summer months, September offers a refreshing respite, with consistent highs remaining steady at about 25°C (78°F). This gentle shift marks the perfect time for outdoor activities and exploring the vibrant local culture, as the cooler evenings invite relaxation under the starry sky. Overall, September’s climate fosters an inviting atmosphere, blending warmth with a touch of autumnal coolness.

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

The chart illustrates September temperature patterns in Monterrey, showcasing daily minimum, maximum, and average temperatures. It highlights the typical range of temperatures throughout the month, providing insights into weather trends.
JanFebMarAprMayJunJulAugSepOctNovDec545759626362616262615755
Data source: Temperature data for Monterrey 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 Monterrey

September marks a significant peak in Monterrey's precipitation, delivering an impressive 251 mm (9.9 in) of rain over 24 days. This month serves as a pivotal transition, where the summer's sweltering heat gives way to the onset of autumn rains. Comparatively, September's rainfall is a substantial increase from the preceding months, particularly following the already substantial figures of June and August. The city experiences a vibrant change as the air turns fresh and revitalized, making it a notable point in Monterrey's climatic calendar. This trend reflects a broader seasonal pattern where summer months culminate in a dramatic surge of precipitation, fostering lush greenery and a lively atmosphere in the region.

September Precipitation Trends in Monterrey

The chart displays monthly precipitation patterns in Monterrey, 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.
JanFebMarAprMayJunJulAugSepOctNovDec363154921672591251622511385628
Data source: Precipitation data for September generated using information from the Copernicus Climate Change Service.
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September Humidity in Monterrey

As September unfolds in Monterrey, Mexico, the city's humidity levels rise to 86%, signaling a transition into the wetter autumn months. This increase follows a summer marked by consistently moderate humidity, hovering around 81-82% from June to August. Interestingly, September's levels mark a notable uptick compared to the preceding months, hinting at the approach of more humid conditions in October and November, which reach peaks of 90% and 91%, respectively. This gradual rise in humidity not only paints a picture of shifting weather patterns but also sets the stage for the lush transformations that accompany the fall season in Monterrey.

September Average Humidity in Monterrey

This chart illustrates the average monthly humidity levels in Monterrey, 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.
JanFebMarAprMayJunJulAugSepOctNovDec88%86%84%81%82%81%81%82%86%90%91%91%
Data source: Humidity data for September generated using information from the Copernicus Climate Change Service.

September UV Index in Monterrey

September in Monterrey, Mexico, continues the trend of intense sun exposure characterized by a UV Index of 14, categorized as extreme with a burn time of just 10 minutes. This month maintains the elevated levels seen throughout the summer, with only slight fluctuations from the previous months of July and August, which also recorded a UV Index of 14 and 15 respectively. As the year transitions into fall, it's essential to stay vigilant about sun protection during outdoor activities. The consistent extreme UV Index serves as a reminder of the sun's potency in this region. For more detailed information, visit Monterrey UV Index.

Maximum UV Index Levels in Monterrey for September

The chart shows the monthly maximum UV Index (UVI) for Monterrey 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.
JanFebMarAprMayJunJulAugSepOctNovDec10121415141515141412109
Data source: Monterrey 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 Monterrey

September in Monterrey, Mexico, welcomes a shift towards the tail end of summer, boasting a delightful 291 hours of sunshine. This marks a slight decrease from the vibrant sunshine of the preceding months, particularly August's 320 hours and July's 330 hours. However, September still offers plenty of sunny days, creating the perfect backdrop for outdoor activities as the heat begins to mellow. As summer transitions to fall, the city's radiant sunshine remains a compelling feature, inviting both locals and tourists to enjoy the beauty of the season. With the sun gradually retreating in hours, one can feel the anticipation of a cooler October, which promises to attract those eager to relish the golden hues of autumn.

Monthly Sunshine Duration in Monterrey: September Highlighted

The September sunshine duration represents the total number of hours Monterrey 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.
JanFebMarAprMayJunJulAugSepOctNovDec237h274h314h314h325h297h330h320h291h305h291h296h
Data source: Monterrey September Sunshine duration data generated using information from the Copernicus Climate Change Service.

Chance of Sun in Monterrey During September

In Monterrey, Mexico, September sees a notable dip in the likelihood of sunny weather, with only a 15% chance of sunshine. This trend stands in stark contrast to the preceding months, particularly February when sunny days are almost guaranteed at 67%. As summer transitions into fall, the sunniest months of the year—like February and the early spring—give way to the wetter, cloudier conditions of September. With just 9% sunshine in June and a gradual increase through late summer, September marks the low point for sun-seekers, making it one of the least favorable months for bright and sunny weather in the region.

Percentage of Sunny Days in September in Monterrey

The chart illustrates the percentage of sunny days in Monterrey 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 Monterrey experiences clear skies throughout the year.
JanFebMarAprMayJunJulAugSepOctNovDec37%67%53%48%35%9%26%29%15%26%34%64%
Data source: Monterrey September chance of sun data, generated using information from the Copernicus Climate Change Service.

Daylight Hours in Monterrey in September

As September arrives in Monterrey, Mexico, the daylight duration settles at 12 hours, mirroring the length of daylight seen in both March and April. This subtle return to a more balanced day-night cycle follows the summer months, which generously offered up to 13 hours of sunlight from May through August. The gradual decrease in daylight not only marks the transition into autumn but also highlights the city's natural rhythm, as it prepares for the shorter days of October and November. This month serves as a perfect blend of light and warmth, inviting residents and visitors alike to relish in the beautiful outdoor experiences Monterrey has to offer.

Average Daylight Hours in Monterrey for September

The chart illustrates the variation in daylight duration in Monterrey throughout the year, with September highlighted. It shows the monthly changes in daylight hours, calculated by summing the hours between sunrise and sunset.
JanFebMarAprMayJunJulAugSepOctNovDec11h 7m11h 31m12h 2m12h 34m13h13h 13m13h 6m12h 43m12h 12m11h 41m11h 14m11h
Data source: Monterrey daylight hours, calculated by summing the hours between sunrise and sunset for each day.

September Winds in Monterrey

As September rolls into Monterrey, Mexico, the city's winds take on a gentler tone, with an average speed of 1.7 m/s (4 mph). This slight decrease from the summer's breezy 2.2 m/s (5 mph) reflects a transitional phase, where the vibrant heat of August begins to wane. Notably, the wind speeds across the year show a consistent pattern, fluctuating around the 4-5 mph mark, with September marking one of the quieter moments. Following the summer months, when the winds pick up a notch, the turn toward fall brings a subtle calm, an invitation to savor the serene beauty of the season as the landscape prepares for its colorful transformation.

Average September Wind Speed in Monterrey

The chart displays monthly wind speed patterns in Monterrey, 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.
JanFebMarAprMayJunJulAugSepOctNovDec1.92.12.12.01.81.62.22.21.7 m/s1.92.11.8
Data source: Monterrey September wind data, generated using information from the Copernicus Climate Change Service.

How September Weather in Monterrey Compares to Other Months

The weather in Monterrey 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 Monterrey and find detailed weather information for every month.

In September, the weather is characterized by a milder average temperature of 17°C (62°F), with a range that can reach a maximum of 25°C (77°F). However, it is also a month with considerable rainfall, recording 251 mm (9.9 in) over 24 days, and the humidity remains high at 86%. In contrast, January offers cooler temperatures, with an average of 12°C (54°F) and a similar maximum of 25°C (78°F), but significantly less precipitation at only 36 mm (1.4 in) over 8 days, coupled with a slightly higher humidity level of 88%. For a more detailed look at winter weather, you can explore Monterrey weather in January.

September and February present distinct weather patterns, reflecting the transition between seasons. In September, temperatures range from a cool 7°C (45°F) at night to a warm 25°C (77°F) during the day, with an average of 17°C (62°F). This month also sees significant rainfall, with 251 mm (9.9 in) distributed over 24 days, contributing to a high humidity level of 86%. In contrast, February features milder temperatures, with a minimum of 1°C (35°F) and a maximum of 29°C (84°F), producing an average of 14°C (57°F). Rainfall drops dramatically to only 31 mm (1.2 in) across just 8 days, while maintaining the same humidity level of 86%. For a closer look at February's weather specifics, you can explore Monterrey weather in February.

September and March showcase quite distinct weather patterns, with September being notably wetter and warmer. In September, temperatures range from a cooler minimum of 7°C (45°F) to a comfortable maximum of 25°C (77°F), accompanied by heavy rainfall averaging 251 mm (9.9 in) over 24 days and high humidity at 86%. In contrast, March offers slightly milder conditions with minimum temperatures dropping to 3°C (38°F) and maximums reaching up to 28°C (83°F). This month experiences significantly less precipitation, totaling 54 mm (2.1 in) over just 11 days and slightly lower humidity at 84%. For more detailed information, you can refer to Monterrey weather in March.

When comparing the weather of September and April, both months exhibit similar average temperatures around 17°C (62°F). However, September experiences a wider temperature range, with minimums of 7°C (45°F) and maximums reaching 25°C (77°F), while April's minimum is slightly cooler at 4°C (39°F) and its maximum is higher at 28°C (83°F).

Precipitation levels also differ significantly; September is notably wetter with 251 mm (9.9 in) over 24 days, contributing to a higher humidity level of 86%. In contrast, April sees much less rain, receiving only 91 mm (3.6 in) across 16 days, leading to a slightly lower humidity of 81%. These differences highlight the transitional nature of both months, with September being marked by increased rainfall and higher humidity, while April is generally drier and warmer. For more detailed insights, check out Monterrey weather in April.

September and May present distinctly different weather patterns, despite their similar average temperatures. September typically features slightly higher humidity at 86%, along with greater precipitation of 251 mm over 24 days, making it one of the wetter months. In contrast, May enjoys a milder humidity level of 82% and less rainfall, totaling 167 mm over 22 days, alongside higher maximum temperatures peaking at 28°C (82°F). For more detailed insights about May weather, you can visit Monterrey weather in May.

In comparing the weather between September and June, we see some notable similarities and differences. September exhibits slightly cooler temperatures, with a minimum of 7°C (45°F) and a maximum of 25°C (77°F), while June's temperatures range from a minimum of 9°C (49°F) to a maximum of 26°C (78°F). Both months experience considerable rainfall, with September receiving around 251 mm (9.9 in) over 24 days and June slightly more at 259 mm (10.2 in) over 25 days. Humidity levels are higher in September at 86%, compared to June's 81%. Overall, while both months are characterized by mild temperatures and frequent rain, September tends to be slightly cooler and more humid. For more detailed information on June weather, check out Monterrey weather in June.

In comparison between September and July weather, both months experience similar maximum temperatures, hovering around 25°C (77°F). However, September typically has a slightly cooler average temperature of 17°C (62°F), compared to July's average of 16°C (61°F). Notably, September is much wetter, with 251 mm (9.9 in) of precipitation over 24 days, whereas July sees only 125 mm (4.9 in) over 16 days. Humidity levels are also higher in September at 86%, compared to July's 81%, making September feel quite a bit more humid. For more details about July weather, you can check out Monterrey weather in July.

In comparing the weather between September and August, we see that both months have a similar average temperature of 17°C (62°F), but September typically experiences slightly cooler minimum temperatures, with a minimum of 7°C (45°F) compared to August's 8°C (47°F). August also boasts a slightly higher maximum temperature, reaching up to 25°C (78°F), whereas September's maximum tapers to 25°C (77°F). However, September is marked by significantly more precipitation, accumulating 251 mm (9.9 in) over 24 days, compared to August's 162 mm (6.4 in) over 20 days. Consequently, September is also slightly more humid, with levels at 86%, versus August's 82%. For more detailed information on August weather, you can check Monterrey weather in August.

September and October exhibit distinct weather patterns, reflecting the transition from late summer to autumn. In September, temperatures range from a minimum of 7°C to a maximum of 25°C, with an average of 17°C. The month is marked by significant rainfall, totaling 251 mm over 24 days, coupled with high humidity at 86%. In contrast, October shows a slight decrease in average temperature to 16°C, with a broader maximum of 27°C. Precipitation also drops considerably to 138 mm across 19 days, while humidity increases to 90%. For more detailed information, you can check the Monterrey weather in October.

In comparing the weather between September and November, we can observe notable differences. September experiences higher temperatures, with an average of 17°C (62°F) and a maximum of 25°C (77°F), while November sees a drop in average temperature to 14°C (57°F), although it still reaches a similar maximum of 25°C (78°F). Additionally, September is significantly wetter, with 251 mm (9.9 in) of precipitation over 24 days, compared to November's much lighter rainfall of 56 mm (2.2 in) over just 12 days. Humidity levels also rise slightly in November, reaching 91%, up from 86% in September. For those interested in a more detailed overview, check out Monterrey weather in November.

September and December exhibit notable differences in weather patterns. In September, temperatures range from a mild minimum of 7°C (45°F) to a warm maximum of 25°C (77°F), with an average of 17°C (62°F). This month is characterized by significant rainfall, with precipitation totaling 251 mm (9.9 in) over 24 days and high humidity at 86%. In contrast, December features a cooler temperature range, with a minimum of -1°C (31°F) and a maximum of 24°C (75°F), averaging around 13°C (55°F). Precipitation drops sharply to 28 mm (1.1 in) over just 7 days, while humidity remains slightly higher at 91%. For more insights on December weather, check out Monterrey weather in December.

Compare Monterrey's Climate with Cities Worldwide

Conclusion: What to Expect From September Weather in Monterrey

As September rolls in, Monterrey experiences a significant shift in weather, marked by a distinct increase in humidity and precipitation compared to the previous months. The average temperature, while still moderate, feels cooler due to the frequent rain showers that grace the city throughout the month. With nearly every day seeing some form of rainfall, September’s lush atmosphere is a refreshing contrast to the drier summer months, offering a unique blend of warmth and moisture. For those looking to understand Monterrey's climatic nuances and dive deeper into its seasonal variations, check out the comprehensive details at Monterrey Climate.