September Weather in Koloa, United States

Last updated: February 24, 2025

September in Koloa, United States offers a warm tropical experience, with maximum temperatures reaching an inviting 30°C (86°F) and an average of 25°C (78°F). The weather can be quite humid, averaging around 82%, which adds to the island's lush ambiance. Visitors should be prepared for occasional rainfall, as the month typically sees 49 mm (1.9 in) of precipitation spread over 16 days. This mix of warmth and moisture is perfect for enjoying the vibrant local scenery while keeping an eye on the changing skies.

September Temperature in Koloa

In September, Koloa experiences a delightful continuation of its warm tropical climate, featuring minimum temperatures around 21°C (71°F) and reaching a cozy average of 25°C (78°F). The mercury peaks at 30°C (86°F), mirroring the highs of August. This month marks a transition as summer gives way to autumn, yet the warmth persists, maintaining a balance that invites beachgoers and outdoor enthusiasts alike. With temperatures consistently hovering in the mid-20s, September remains an ideal time for sun-soaked adventures or leisurely strolls along the picturesque shores, making the most of Koloa's vibrant landscape before the cooler months set in.

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

The chart illustrates September temperature patterns in Koloa, showcasing daily minimum, maximum, and average temperatures. It highlights the typical range of temperatures throughout the month, providing insights into weather trends.
JanFebMarAprMayJunJulAugSepOctNovDec717070727476777878767472
Data source: Temperature data for Koloa 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 Koloa

In September, Koloa experiences a marginal dip in precipitation, recording 49 mm (1.9 in) of rainfall over 16 days. This signals a transition into the drier months as the summer heat starts to recede. The moisture levels show a slight decrease compared to the previous peak in March with 136 mm (5.4 in), while still maintaining a relatively consistent pattern seen throughout the late summer months, where similar amounts were observed in July and August. As September draws to a close and the region prepares for October, which typically brings increased rainfall, the trend suggests a gradual shift towards the wetter season ahead.

September Precipitation Trends in Koloa

The chart displays monthly precipitation patterns in Koloa, 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.
JanFebMarAprMayJunJulAugSepOctNovDec3984136625280545449895597
Data source: Precipitation data for September generated using information from the Copernicus Climate Change Service.
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September Humidity in Koloa

In Koloa, the month of September sees a humidity level of 82%, maintaining the elevated moisture typical of the late summer months. This time of year lies within a trend of gradually increasing humidity that begins in the spring, peaking in July and August at 83%. Following this peak, humidity levels remain steady in September before experiencing a slight decline into October. This consistency suggests that while summer’s warmth lingers, the moisture in the air starts to ease, hinting at the transition to the cooler, drier autumn months ahead.

September Average Humidity in Koloa

This chart illustrates the average monthly humidity levels in Koloa, 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.
JanFebMarAprMayJunJulAugSepOctNovDec78%79%78%81%82%82%83%83%82%81%80%79%
Data source: Humidity data for September generated using information from the Copernicus Climate Change Service.

September UV Index in Koloa

In September, Koloa experiences a slightly lower UV Index of 12, categorized as extreme, which indicates consistent high sun exposure and a burn time of just 10 minutes. This continues the trend of elevated UV levels seen throughout the summer months, where the Index peaked at 13 from May to August. With the transition into fall, UV levels remain significant, though they start to taper off leading into October, when the Index drops to 10. As such, residents and visitors alike should remain vigilant with sun protection, particularly in the early days of September, where the powerful rays are still prevalent. For more details on Koloa's UV Index throughout the year, visit Koloa UV Index.

Maximum UV Index Levels in Koloa for September

The chart shows the monthly maximum UV Index (UVI) for Koloa 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.
JanFebMarAprMayJunJulAugSepOctNovDec810111213131313121087
Data source: Koloa 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 Koloa

As summer gently transitions into fall, September in Koloa, United States, enjoys a vibrant 313 hours of sunshine. This inviting amount of sunlight marks a slight decline from the sun-drenched peak of 348 hours in July, yet it still reflects a robust brightness that characterizes the region's climate. Following the trend of abundant sunlight in the summer months, September maintains a warm glow, outpacing the earlier months of the year and setting the stage for a comfortable transition into autumn. As the days gradually shorten, Koloa remains bathed in ample sunshine, offering idyllic weather for outdoor activities and a lingering summer vibe.

Monthly Sunshine Duration in Koloa: September Highlighted

The September sunshine duration represents the total number of hours Koloa 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.
JanFebMarAprMayJunJulAugSepOctNovDec216h256h280h303h332h331h348h335h313h296h266h254h
Data source: Koloa September Sunshine duration data generated using information from the Copernicus Climate Change Service.

Chance of Sun in Koloa During September

Koloa, United States, enjoys a notable balance of sunshine in September, with a 52% chance of sun illuminating the skies. This figure falls in line with the region's typical weather trends, demonstrating a mild rebound from the summer's peak at 58% in August. As the year progresses into autumn, the likelihood of sunny days remains relatively steady, with October and November not straying far behind at 55% each, suggesting that Koloa's enchanting climate continues to favor outdoor activities even as summer fades. The overall consistency in sunny chances throughout the year highlights the area's appeal for sun-seekers looking for that perfect getaway.

Percentage of Sunny Days in September in Koloa

The chart illustrates the percentage of sunny days in Koloa 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 Koloa experiences clear skies throughout the year.
JanFebMarAprMayJunJulAugSepOctNovDec51%50%43%49%52%56%44%58%52%55%55%33%
Data source: Koloa September chance of sun data, generated using information from the Copernicus Climate Change Service.

Daylight Hours in Koloa in September

As September arrives in Koloa, the sunlight graces the island with 12 hours of daylight, maintaining a balance that reflects the waning summer. This month marks a transition, as daylight hours have peaked during the vibrant summer months of June and July at 13 hours, before gradually retreating as fall approaches. The trend showcases a steady decline in available sunlight, beginning from August and continuing into October, where daylight decreases to 11 hours. This rhythm of daylight not only highlights the island's seasonal changes but also invites residents and visitors alike to savor the glorious sunlit days while they last, setting the stage for the warm embrace of autumn.

Average Daylight Hours in Koloa for September

The chart illustrates the variation in daylight duration in Koloa throughout the year, with September highlighted. It shows the monthly changes in daylight hours, calculated by summing the hours between sunrise and sunset.
JanFebMarAprMayJunJulAugSepOctNovDec10h 57m11h 25m12h 2m12h 39m13h 11m13h 26m13h 17m12h 50m12h 13m11h 36m11h 3m10h 48m
Data source: Koloa daylight hours, calculated by summing the hours between sunrise and sunset for each day.

September Winds in Koloa

As September rolls in Koloa, the gentle breezes bring an average wind speed of 3.9 m/s (9 mph), marking a slight uptick from August's 3.8 m/s (8 mph). This month continues the trend of mild winds that characterize the late summer, offering an inviting backdrop for outdoor activities. Notably, September's winds are tied with October's average, suggesting a consistent pattern as the seasons begin to shift. As we look back over the year, the wind speeds show a gentle ebb and flow, peaking in July at 4.3 m/s (10 mph), while the winter months often bring more subdued breezes, with November dipping to 2.7 m/s (6 mph). Overall, September's inviting gusts hint at the transition from summer warmth to the cooler, breezier days of fall.

Average September Wind Speed in Koloa

The chart displays monthly wind speed patterns in Koloa, 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.
JanFebMarAprMayJunJulAugSepOctNovDec3.83.54.23.33.43.24.33.83.9 m/s3.92.74.1
Data source: Koloa September wind data, generated using information from the Copernicus Climate Change Service.

How September Weather in Koloa Compares to Other Months

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

In September, the weather is generally warmer, with average temperatures around 25°C (78°F) and maximums reaching up to 30°C (86°F). The month also experiences higher humidity at 82% and more frequent rainfall, with precipitation averaging 49 mm (1.9 in) over 16 days. In contrast, January presents a cooler climate, featuring an average temperature of 22°C (71°F) and a maximum of 26°C (79°F). Additionally, January sees less precipitation, with around 38 mm (1.5 in) over just 10 days and slightly lower humidity at 78%. For more detailed information about January weather, check this link: Koloa weather in January.

September and February present distinct weather patterns, reflecting the transition from summer to winter in many regions. September boasts warmer temperatures, with an average of 25°C (78°F) and highs reaching up to 30°C (86°F), while February's temperatures are cooler, averaging 21°C (70°F) and peaking at 26°C (79°F). Additionally, September experiences a slightly lower level of precipitation at 49 mm (1.9 in) compared to February's 84 mm (3.3 in), although both months share a similar number of rainy days, with precipitation occurring on about 16 days in September and 15 days in February. Humidity remains fairly high in both months, with September at 82% and February at 79%. For those looking to know more about specific weather conditions during this season, you can check Koloa weather in February.

September and March present distinct weather patterns, offering a notable comparison. In September, temperatures typically range from a minimum of 21°C (71°F) to a maximum of 30°C (86°F), with an average of 25°C (78°F). The month experiences about 49 mm (1.9 in) of precipitation spread over 16 days, alongside relatively high humidity at 82%. In contrast, March has slightly cooler temperatures, with a minimum of 18°C (64°F) and a maximum of 26°C (80°F), averaging 21°C (71°F). However, it sees a higher precipitation level of 136 mm (5.4 in) over 19 days, with humidity at 78%. This showcases March as a wetter month compared to September. For more detailed information on Koloa's weather during March, you can check Koloa weather in March.

When comparing the weather in September and April, September tends to be warmer, with average temperatures ranging from a minimum of 21°C (71°F) to a maximum of 30°C (86°F), while April has cooler averages, with minimums of 18°C (64°F) and maximums of 27°C (80°F). Precipitation is slightly lower in September, totaling 49 mm (1.9 in) over about 16 days, compared to April's 61 mm (2.4 in) over 17 days. Interestingly, the humidity levels are fairly similar, with September at 82% and April at 81%. For those interested in a more detailed look at April weather, you can check Koloa weather in April.

When comparing the weather between September and May, we find that September typically enjoys slightly warmer temperatures, with an average of 25°C (78°F) compared to May’s 23°C (74°F). September reaches higher maximum temperatures, averaging 30°C (86°F) versus May’s peak of 28°C (83°F). Precipitation levels are fairly similar, with September receiving 49 mm (1.9 in) over 16 days and May experiencing a bit more at 52 mm (2.1 in) across 17 days. Both months share the same humidity level of 82%, making the air feel consistently comfortable. For more specific details on Koloa weather in May, you can check this link: Koloa weather in May.

When comparing the weather in September and June, we see similar minimum temperatures, both starting at around 21°C (71°F). However, September typically enjoys slightly warmer average and maximum temperatures, with averages reaching 25°C (78°F) and highs of 30°C (86°F), compared to June's averages of 24°C (76°F) and a maximum of 28°C (83°F). Precipitation levels are notably different, with September experiencing 49 mm (1.9 in) over 16 days, while June sees a higher total of 80 mm (3.1 in) over 17 days. Humidity remains consistent in both months at 82%. For more specific details, you can check Koloa weather in June.

When comparing the weather in September and July, both months exhibit similar temperature ranges, with September experiencing slightly higher maximum temperatures (30°C or 86°F) compared to July's peak at 29°C (84°F). The average temperatures are nearly identical, each hovering around 25°C (77-78°F). However, September sees a reduction in overall precipitation, totaling 49 mm (1.9 in) over 16 days, whereas July receives 54 mm (2.1 in) with rain on 23 days. Humidity levels remain quite comparable, with September averaging 82% and July at 83%. For more detailed insights into July's weather, check out Koloa weather in July.

In comparing the weather of September and August, both months exhibit similar temperature ranges, with minimums around 21°C (70°F) and maximums reaching up to 30°C (86°F). The average temperature remains consistent at 25°C (78°F) for both months. However, September sees slightly less precipitation at 49 mm (1.9 in) over 16 days, compared to August's 54 mm (2.1 in) over 18 days. Humidity levels are also comparable, with September at 82% and August slightly higher at 83%. For those interested in learning more about the weather conditions in August, you can visit Koloa weather in August.

In September, the weather tends to be warm with temperatures ranging from a minimum of 21°C (71°F) to a maximum of 30°C (86°F), averaging around 25°C (78°F). This month sees around 49 mm (1.9 in) of precipitation over 16 days, accompanied by relatively high humidity of 82%. In contrast, October experiences slightly cooler temperatures, with a minimum of 20°C (68°F) and a maximum of 29°C (85°F), while maintaining the same average of 25°C (76°F). However, October is wetter, with precipitation reaching 89 mm (3.5 in) over 20 days, and humidity remains close at 81%. For more detailed information, you can check Koloa weather in October.

In September, the weather tends to be warm and humid, with average temperatures ranging from a minimum of 21°C (71°F) to a maximum of 30°C (86°F). The month experiences approximately 49 mm (1.9 in) of precipitation over about 16 days. In contrast, November sees slightly cooler temperatures, with a minimum of 19°C (67°F) and a maximum of 28°C (83°F), with an average temperature of 24°C (75°F). Although November has a bit more rain, totaling around 55 mm (2.2 in) over 19 days, the humidity remains relatively similar at 80%. For a more detailed look at Koloa weather in November, visit Koloa weather in November.

In comparing the weather in September and December, we see a noticeable shift in temperature and precipitation patterns. September enjoys warmer temperatures, with averages around 25°C (78°F) and maximums reaching up to 30°C (86°F), while December's temperatures are cooler, averaging 22°C (72°F) and peaking at 27°C (81°F). Additionally, December experiences greater precipitation, with an average of 97 mm (3.8 in) spread over the same number of days as September, which has 49 mm (1.9 in) of rain. Despite the increased rainfall in December, the humidity remains relatively similar in both months, hovering around 79% in December compared to 82% in September. For more detailed information about December weather specifics, visit Koloa weather in December.

Compare Koloa's Climate with Cities Worldwide

Conclusion: What to Expect From September Weather in Koloa

As September rolls into Koloa, the summer warmth begins to wane, yet it still boasts a pleasantly mild climate with daytime temperatures comfortably nestled between highs and lows. While the humidity lingers at a relatively high 82%, occasional rain showers, occurring on about half the month’s days, bring a refreshing change that sets September apart from the drier months of summer. This transitional weather offers a unique blend of tropical beauty and gentle rainfall, making it an inviting time for both relaxation and exploration. To learn more about this enchanting destination's yearly weather patterns, check out Koloa Climate.