September Weather in Carolina, Puerto Rico

Last updated: August 31, 2025

September in Carolina, Puerto Rico offers a tropical climate characterized by warm temperatures and considerable humidity. The maximum daily temperature can soar to 32°C (90°F), with an average of 28°C (82°F), providing ideal conditions for beach activities. However, residents and visitors should prepare for frequent rainfall, as the month sees about 173 mm (6.8 in) of precipitation over 23 days, contributing to a humidity level of 79%. Despite the rain, the lush environment and vibrant atmosphere make September a unique time to experience the beauty of Puerto Rico.

September Temperature in Carolina

In September, temperatures in Carolina, Puerto Rico remain warm and inviting, with minimums around 24°C (76°F) and averaging a comfortable 28°C (82°F). Highs can reach up to 32°C (90°F), maintaining the trend of summer warmth as the month progresses. This pattern reflects the gradual transition from the sizzling summer months of July and August, where temperatures were similarly warm, highlighting the region's tropical climate. Those seeking sunny beach days will find September a delightful choice, as the lingering warmth invites outdoor activities and relaxation. As the season shifts toward autumn, temperatures begin to cool slightly, but the charm of Carolina's vibrant atmosphere and balmy weather continues to entice visitors.

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

The chart illustrates September temperature patterns in Carolina, showcasing daily minimum, maximum, and average temperatures. It highlights the typical range of temperatures throughout the month, providing insights into weather trends. In Carolina, September typically has an average temperature of {2}°C ({3}°F), with highs reaching up to {4}°C ({5}°F) and lows dropping to around {6}°C ({7}°F).
JanFebMarAprMayJunJulAugSepOctNovDec777677788081828282817978
Data source: Temperature data for Carolina 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 Carolina

September in Carolina, Puerto Rico, stands out as the wettest month of the year, with a substantial precipitation amount of 173 mm (6.8 in) recorded over 23 days. This sharp spike in rainfall, compared to an average of just 99 mm (3.9 in) in August, highlights the transition into the rainy season. The month marks a significant increase in both the frequency and intensity of rain, as it witnesses a rise in precipitation days to 23. Following the pattern of escalating wetness, October also retains a high level of rainfall, though it slightly tapers off to 145 mm (5.7 in). This trend underscores the importance of September as a pivotal time for water replenishment, setting the stage for the drier months ahead.

September Precipitation Trends in Carolina

The chart displays monthly precipitation patterns in Carolina, 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. In Carolina, September typically receives around {2} mm ({3} inches) of precipitation spread over approximately {4} days.
JanFebMarAprMayJunJulAugSepOctNovDec394367566468879917314510651
Data source: Precipitation data for September generated using information from the Copernicus Climate Change Service.
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September Humidity in Carolina

September marks a slight dip in humidity in Carolina, Puerto Rico, with levels averaging 79%, following the peak of 80% experienced in both July and August. This gradual decrease hints at a transition from the sweltering summer months to milder fall conditions. Interestingly, the humidity during September remains relatively high compared to earlier months in the year, such as January, February, and March, which hover around 75%. The trend of elevated humidity through the summer suggests that while the heat may be less intense than in peak summer, the tropical climate still holds onto significant moisture, creating that characteristic warmth felt throughout the island. It’s a perfect time to enjoy the lush surroundings, as the balance of humidity ensures a vibrant landscape.

September Average Humidity in Carolina

This chart illustrates the average monthly humidity levels in Carolina, with September’s data highlighted for easy comparison. It shows the fluctuation in humidity throughout the year, helping you understand how conditions vary by season. In September, average humidity in Carolina is approximately {2}%, offering insight into how humid the weather typically is during this month.
JanFebMarAprMayJunJulAugSepOctNovDec76%75%74%75%75%77%80%80%79%78%78%76%
Data source: Humidity data for September generated using information from the Copernicus Climate Change Service.

September UV Index in Carolina

In September, residents and visitors of Carolina, Puerto Rico continue to face an extreme UV Index of 13, identical to the preceding months of August and March through June. This trend of high UV levels underscores the importance of sun safety, as the burn time remains a mere 10 minutes for unprotected skin. Such consistency in the UV Index highlights the tropical climate's intensity, reminding everyone to apply sunscreen and seek shade during midday. As you soak up the beautiful Puerto Rican sun this month, stay vigilant about protecting your skin. For more details on UV levels throughout the year, check out the Carolina UV Index.

Maximum UV Index Levels in Carolina for September

The chart shows the monthly maximum UV Index (UVI) for Carolina 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. In September, the maximum UV index in Carolina typically reaches {2}, which falls under the {3} exposure category.
JanFebMarAprMayJunJulAugSepOctNovDec911131314131213131298
Data source: Carolina 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 Carolina

September in Carolina, Puerto Rico, reveals a delightful transition as the summer sun begins to wane, offering 313 hours of radiant sunshine. This month continues a trend of plentiful sunlight that has been consistent since early spring, peaking at 356 hours in May. While September's sunshine dips slightly from the summer's peak, it retains a charm that complements the warm, tropical ambiance. As the calendar shifts to autumn, the balance of sunshine and cooling breezes creates a perfect backdrop for outdoor activities, making Carolina an inviting destination. Although October matches September’s sunlight, the subtly shifting landscape hints at the seasonal changes to come, ensuring that the allure of Puerto Rican sunshine remains ever-present.

Monthly Sunshine Duration in Carolina: September Highlighted

The September sunshine duration represents the total number of hours Carolina 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.
JanFebMarAprMayJunJulAugSepOctNovDec257h303h346h346h356h343h353h349h313h313h299h319h
Data source: Carolina September Sunshine duration data generated using information from the Copernicus Climate Change Service.

Chance of Sun in Carolina During September

In September, the likelihood of sunny weather in Carolina, Puerto Rico hovers around 48%, suggesting a moderate chance for sunshine as summer transitions into fall. This aligns closely with the trends observed in the late summer months, where the chances of clear skies are consistently lower than earlier in the year, particularly compared to February's peak at 70%. After the summer months of June and July, which offer the least sun at 24% and 43% respectively, September marks a subtle recovery in sunshine potential, although it remains slightly below the yearly average. With October closely mirroring September's conditions at 49%, visitors can anticipate a balanced blend of sun and occasional rain, perfect for enjoying the lush landscapes and vibrant culture of the region.

Percentage of Sunny Days in September in Carolina

The chart illustrates the percentage of sunny days in Carolina 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 Carolina experiences clear skies throughout the year.
JanFebMarAprMayJunJulAugSepOctNovDec51%70%64%49%56%24%43%41%48%49%61%64%
Data source: Carolina September chance of sun data, generated using information from the Copernicus Climate Change Service.

Daylight Hours in Carolina in September

September in Carolina, Puerto Rico, brings 12 hours of daylight, perfectly aligning with the latter part of summer's warm embrace. As the month progresses, daylight remains consistent with August, showcasing a comforting stability amid the seasonal transitions. Leading up to this, daylight duration peaked at 13 hours in both June and July, gradually tapering down as autumn approaches, while the winter months of January through March witness a return to shorter days with 11 to 12 hours of daylight. This seasonal rhythm not only enhances the natural beauty of the region but also offers residents and visitors alike ample time to soak in the vibrant surroundings before the days shorten further.

Average Daylight Hours in Carolina for September

The chart illustrates the variation in daylight duration in Carolina throughout the year, with September highlighted. It shows the monthly changes in daylight hours, calculated by summing the hours between sunrise and sunset.
JanFebMarAprMayJunJulAugSepOctNovDec11h 9m11h 32m12h 2m12h 33m12h 59m13h 12m13h 5m12h 42m12h 12m11h 41m11h 15m11h 2m
Data source: Carolina daylight hours, calculated by summing the hours between sunrise and sunset for each day.

September Winds in Carolina

In September, the winds in Carolina, Puerto Rico exhibit a notable dip, averaging 3.2 m/s (7 mph), the lowest for the year. This gentle breeze marks a transition from the stronger gusts experienced in the summer months, particularly July, which boasts an average of 5.3 m/s (12 mph). As the seasons shift, one can observe a pattern where the wind speeds typically peak in the summer and gradually decline into the fall, with September often heralding this mellow phase. While the warmth of summer lingers, the winds slow, providing a serene atmosphere as the island gently eases into the cooler months ahead. This calmness in September sets the stage for more tranquil and reflective days, inviting visitors to enjoy the island's beauty at a relaxed pace.

Average September Wind Speed in Carolina

The chart displays monthly wind speed patterns in Carolina, 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.
JanFebMarAprMayJunJulAugSepOctNovDec4.15.24.53.84.44.95.34.63.2 m/s3.53.74.4
Data source: Carolina September wind data, generated using information from the Copernicus Climate Change Service.

How September Weather in Carolina Compares to Other Months

Weather in Carolina varies notably across the year, with each month offering distinct climate conditions. This page compares September’s weather to other months in Carolina, focusing on differences in temperature, rainfall, humidity, and UV levels.

In comparing the weather between September and January, September is notably warmer and wetter. With average temperatures reaching 28°C (82°F) and maximums climbing to 32°C (90°F), it contrasts sharply with January's cooler average of 25°C (77°F) and maximum of 29°C (85°F). Additionally, September experiences significantly higher precipitation, totaling 173 mm (6.8 in) over 23 days, while January sees a much drier climate with only 38 mm (1.5 in) across 12 days. Humidity levels are slightly elevated in September at 79%, compared to January's 76%. For more detailed insights, check Carolina weather in January.

September and February offer distinct weather experiences. In September, temperatures are generally warmer, with an average of 28°C (82°F) and maximums reaching up to 32°C (90°F). The month is notably wetter, receiving about 173 mm (6.8 inches) of rain over 23 days and maintaining high humidity levels at 79%. In contrast, February presents milder conditions with an average temperature of 25°C (77°F) and highs peaking at 29°C (85°F). Precipitation is significantly lower, totaling just 43 mm (1.7 inches) over 12 days, and humidity is slightly less at 75%. For more detailed information, visit Carolina weather in February.

In September, the weather tends to be warmer and more humid, with average temperatures around 28°C (82°F) and highs reaching up to 32°C (90°F). This month is also characterized by significant rainfall, averaging 173 mm (6.8 in) over 23 rainy days, leading to a humidity level of 79%. In contrast, March offers a milder climate, featuring average temperatures of 25°C (77°F) with maximums of 30°C (86°F) and a lower overall precipitation of 67 mm (2.6 in) spread over just 14 days, resulting in a humidity of 74%. For a more detailed comparison, you can check out Carolina weather in March.

When comparing the weather in September and April, September tends to be warmer with average temperatures around 28°C (82°F) and a maximum reaching up to 32°C (90°F), while April's average is slightly cooler at 26°C (78°F), peaking at 31°C (88°F). September also experiences significantly more precipitation, with 173 mm (6.8 in) spread across 23 days, compared to April's 56 mm (2.2 in) over just 10 days. Humidity levels are also higher in September at 79%, while April maintains a more comfortable 75%. For further details, check Carolina weather in April.

In comparing the weather of September and May, we find some intriguing similarities and differences. Both months experience warm temperatures, with September showcasing a slightly higher average temperature of 28°C (82°F) compared to May's 27°C (80°F). While both months can reach a maximum of 32°C (90°F), September tends to be wetter, with a significant 173 mm (6.8 in) of precipitation over 23 days, whereas May is much drier, receiving only 64 mm (2.5 in) across 13 days. Humidity levels are also marginally higher in September, averaging 79% compared to May's 75%. For more detailed weather insights, you can check out Carolina weather in May.

September weather presents a notable comparison to June, particularly in terms of precipitation and humidity. While both months share similar temperature ranges—with minimums around 24°C (75-76°F) and maximums of 32°C (90°F)—September tends to be more humid with an average of 79% compared to June's 77%. However, September experiences significantly higher levels of rainfall, receiving 173 mm (6.8 in) over 23 days, while June records only 68 mm (2.7 in) across 15 days. This increase in precipitation in September indicates a shift towards wetter conditions as the year progresses. For more details on June weather, visit Carolina weather in June.

When comparing the weather in September and July, both months share similar temperature ranges, with minimums at 24°C (76°F), averages around 28°C (82°F), and maximums reaching 32°C (90°F). However, September is notably wetter, receiving 173 mm (6.8 in) of precipitation over 23 days, compared to July's 87 mm (3.4 in) over 18 days. Humidity levels are slightly lower in July at 80%, compared to September's 79%. For more details on the weather patterns in July, you can refer to Carolina weather in July.

In comparing the weather of September and August, we can see that both months share similar temperature ranges, with a minimum of 24°C (76°F), an average of 28°C (82°F), and a maximum of 32°C (90°F). However, September experiences significantly more rainfall, totaling 173 mm (6.8 in) across 23 days, compared to August’s 99 mm (3.9 in) over 18 days. The humidity levels are quite close, with September at 79% and August slightly higher at 80%. This increased precipitation in September indicates a shift towards more unsettled weather as summer comes to a close. For a more detailed look at weather patterns, you can visit Carolina weather in August.

September and October display some similarities in their weather patterns, but notable differences exist as well. Both months maintain a minimum temperature of around 24°C (75-76°F), with October experiencing a slightly lower average temperature of 27°C (81°F) compared to September's 28°C (82°F). The maximum temperatures remain consistent, peaking at 32°C (89-90°F) in both months. However, October receives less precipitation, totaling 145 mm (5.7 in) over 22 days, compared to September's 173 mm (6.8 in) across 23 days. Humidity is also slightly lower in October at 78%, compared to September's 79%. For more detailed information on October weather, check out Carolina weather in October.

In September, the weather tends to be warmer and more humid, with temperatures ranging from a minimum of 24°C (76°F) to a maximum of 32°C (90°F) and an average temperature of 28°C (82°F). This month also experiences significant rainfall, totaling 173 mm (6.8 in) over 23 days, contributing to high humidity levels at 79%.

In contrast, November sees slightly cooler temperatures, with a minimum of 23°C (74°F), an average of 26°C (80°F), and a maximum of 31°C (87°F). The month is drier, receiving only 106 mm (4.2 in) of precipitation over 16 days, resulting in a marginally lower humidity level of 78%. For more information on the weather conditions in November, you can check Carolina weather in November.

In September, the weather tends to be warmer and wetter, with average temperatures reaching 28°C (82°F) and maximums of 32°C (90°F). This month experiences substantial rainfall, accumulating 173 mm (6.8 in) over 23 days and maintaining a high humidity level of 79%. In contrast, December offers milder temperatures, averaging 26°C (78°F) with maximums around 31°C (87°F) and only 51 mm (2.0 in) of precipitation over 16 days. Humidity drops slightly to 76%, making December feel a bit more comfortable than the humid conditions of September. For a detailed overview of what to expect, check out Carolina weather in December.

Compare Carolina's Climate with Cities Worldwide

Conclusion: What to Expect From September Weather in Carolina

As summer transitions to autumn, September in Carolina showcases a notable shift in weather patterns. With higher humidity levels than the preceding months, the air feels more tropical, inviting occasional rain that graces the region more frequently. While temperatures remain generally warm, the month brings a unique blend of heat and moisture, creating a vibrant atmosphere. However, the significant precipitation serves as a reminder of the changing seasons, offering lush landscapes that contrast with the drier summer period. For a more in-depth look at year-round conditions, explore Carolina Climate.