September Weather in Kailua-Kona, United States

Last updated: February 24, 2025

In Kailua-Kona, United States, the weather in September offers a warm and humid experience, with maximum temperatures averaging 28°C (82°F) and minimums dropping to a comfortable 20°C (68°F). The month is characterized by a significant amount of rainfall, totaling 286 mm (11.3 in) over 28 days, contributing to the lush landscapes of this beautiful coastal town. With an average humidity level of 82%, visitors can expect a tropical atmosphere that enhances the stunning natural scenery, perfect for adventure seekers and those looking to unwind under the sun.

September Temperature in Kailua-Kona

In Kailua-Kona, September marks the tail end of summer, showcasing delightful warm temperatures that invite beachgoers to enjoy the sun. With a minimum temperature of 20°C (68°F) and a maximum reaching up to 28°C (82°F), the average temperature hovers around a pleasant 24°C (75°F). This month reflects a slight increase from August’s warmth, demonstrating a consistent pattern of rising temperatures as the year progresses. As the days remain balmy and inviting, September becomes a sweet spot for outdoor activities, making it an ideal time to soak in the vibrant Hawaiian atmosphere before the cooler months arrive.

September Weather in Kailua-Kona: Daily Temperature Highs, Lows, and Averages

The chart illustrates September temperature patterns in Kailua-Kona, showcasing daily minimum, maximum, and average temperatures. It highlights the typical range of temperatures throughout the month, providing insights into weather trends.
JanFebMarAprMayJunJulAugSepOctNovDec707070717273747575747372
Data source: Temperature data for Kailua-Kona 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 Kailua-Kona

In September, Kailua-Kona sees a notable precipitation decrease, with 286 mm (11.3 in) of rainfall measured over 28 days. This marks a drop from the record-high August totals of 458 mm (18.0 in), suggesting a transition away from the peak of the rainy season. Despite this reduction, September still stands as one of the wetter months of the year, indicating the lingering effects of summer precipitation patterns. As the region moves into October, the anticipated decline continues, with rain totals forecasted to settle at approximately 230 mm (9.0 in), reflecting a seasonal shift that emphasizes the dynamic weather variability of Kailua-Kona.

September Precipitation Trends in Kailua-Kona

The chart displays monthly precipitation patterns in Kailua-Kona, 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.
JanFebMarAprMayJunJulAugSepOctNovDec133149129212332365387458286230143189
Data source: Precipitation data for September generated using information from the Copernicus Climate Change Service.
Choose your preferred precipitation unit

September Humidity in Kailua-Kona

September in Kailua-Kona, United States, sees a humidity level of 82%, maintaining a trend of elevated moisture that has been building since the warmer months. Following a peak of 84% in August, humidity slightly decreases, yet remains consistent with the higher readings typically recorded from June through October. This pattern illustrates that while September marks the transition toward drier fall conditions, it still retains a level of humidity that reflects the lingering warmth of summer. Overall, the month exemplifies Kailua-Kona’s tropical climate, where humidity remains a defining characteristic throughout the year.

September Average Humidity in Kailua-Kona

This chart illustrates the average monthly humidity levels in Kailua-Kona, 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.
JanFebMarAprMayJunJulAugSepOctNovDec79%79%77%80%80%82%83%84%82%83%83%81%
Data source: Humidity data for September generated using information from the Copernicus Climate Change Service.

September UV Index in Kailua-Kona

In September, Kailua-Kona experiences a UV Index of 13, categorizing the sun exposure as extreme with a burn time reduced to just 10 minutes. This places September slightly lower than the peak months of July and August, which boast a UV Index of 14. Overall, the UV Index remains quite high throughout the summer months into early autumn, reflecting a trend of intense sun exposure from February through October. As the year progresses, the UV Index begins to taper off, transitioning into the very high categories of November and December. For those looking to enjoy sunshine safely while in Kailua-Kona, it’s crucial to stay informed and protected, especially during these peak times. For more detailed information, visit Kailua-Kona UV Index.

Maximum UV Index Levels in Kailua-Kona for September

The chart shows the monthly maximum UV Index (UVI) for Kailua-Kona 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.
JanFebMarAprMayJunJulAugSepOctNovDec811121313131414131298
Data source: Kailua-Kona 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 Kailua-Kona

In Kailua-Kona, September greets visitors with a generous 311 hours of sunshine, continuing the trend of abundant daylight that characterizes the summer months. Following the peak sunshine of July and August, where daylight reached 338 and 328 hours respectively, September still offers plenty of warmth and brightness, making it an ideal time for outdoor activities and exploration. As the year progresses into October, sunshine begins to wane slightly, dropping to 297 hours, yet September stands out as a vibrant month, resonating with the lingering energy of summer while hinting at the approaching autumn. With its idyllic weather and breathtaking scenery, September in Kailua-Kona is perfect for those seeking sun-soaked adventures.

Monthly Sunshine Duration in Kailua-Kona: September Highlighted

The September sunshine duration represents the total number of hours Kailua-Kona 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.
JanFebMarAprMayJunJulAugSepOctNovDec223h255h282h303h331h331h338h328h311h297h271h262h
Data source: Kailua-Kona September Sunshine duration data generated using information from the Copernicus Climate Change Service.

Chance of Sun in Kailua-Kona During September

In Kailua-Kona, September offers a 33% chance of sunny weather, making it a relatively reliable month for sunshine when compared to the summer's dipped probabilities. The trend showcases that as summer fades, the likelihood of clear skies begins to creep up slightly, with September's sunny days outpacing the peaks seen in June and July. This transitional month provides a unique opportunity to enjoy the tail end of summer warmth while basking in sunlight that graces the island more frequently than in the height of summer. Overall, September strikes a balance, serving as a favorable window for those seeking the beauty of the Hawaiian sun.

Percentage of Sunny Days in September in Kailua-Kona

The chart illustrates the percentage of sunny days in Kailua-Kona 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 Kailua-Kona experiences clear skies throughout the year.
JanFebMarAprMayJunJulAugSepOctNovDec35%46%46%44%29%26%25%31%34%38%39%29%
Data source: Kailua-Kona September chance of sun data, generated using information from the Copernicus Climate Change Service.

Daylight Hours in Kailua-Kona in September

As summer transitions into fall in Kailua-Kona, September offers a delightful 12 hours of daylight, a continuation of the sun-drenched days that characterize the previous months. This month marks a gentle decline from the peak of 13 hours seen in June, July, and August, signaling the gradual shift as daylight hours begin to decrease. Despite this reduction, September still boasts ample sunlight for beach-goers and outdoor enthusiasts alike. Following this pattern, October will further narrow daylight to 11 hours, indicating the onset of shorter days as the year progresses. Overall, Kailua-Kona's September daylight duration provides a perfect backdrop for enjoying the island's stunning landscapes and vibrant culture before the days grow shorter.

Average Daylight Hours in Kailua-Kona for September

The chart illustrates the variation in daylight duration in Kailua-Kona throughout the year, with September highlighted. It shows the monthly changes in daylight hours, calculated by summing the hours between sunrise and sunset.
JanFebMarAprMayJunJulAugSepOctNovDec11h 5m11h 30m12h 2m12h 36m13h 3m13h 17m13h 9m12h 44m12h 12m11h 39m11h 11m10h 57m
Data source: Kailua-Kona daylight hours, calculated by summing the hours between sunrise and sunset for each day.

September Winds in Kailua-Kona

As September rolls into Kailua-Kona, the average wind speed settles at a gentle 2.2 m/s (5 mph), reflective of the patterns established throughout the year. With only slight fluctuations, this month mirrors the calmness of both April and October, suggesting a soothing transition towards the island's tranquil fall. Interestingly, the wind picks up slightly in the warmer months of June and July at 2.5 m/s (6 mph), perhaps bringing a refreshing breeze to counterbalance the heat. Overall, the wind remains consistently mild, creating an inviting atmosphere perfect for beachgoers and outdoor enthusiasts alike.

Average September Wind Speed in Kailua-Kona

The chart displays monthly wind speed patterns in Kailua-Kona, 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.
JanFebMarAprMayJunJulAugSepOctNovDec2.12.42.22.12.32.52.52.32.2 m/s2.22.22.2
Data source: Kailua-Kona September wind data, generated using information from the Copernicus Climate Change Service.

How September Weather in Kailua-Kona Compares to Other Months

The weather in Kailua-Kona 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 Kailua-Kona and find detailed weather information for every month.

September and January boast distinct weather patterns that reflect the transition between seasons. In September, temperatures range from a minimum of 20°C (68°F) to a maximum of 28°C (82°F), with an average of 24°C (75°F). This month is characterized by high humidity at 82% and substantial precipitation, totaling 286 mm (11.3 in) over 28 days. In contrast, January presents slightly cooler temperatures, with minimums of 17°C (63°F) and maximums of 26°C (80°F), averaging 21°C (70°F). Precipitation in January is lower, totaling 133 mm (5.3 in) over 19 days, along with a humidity level of 79%. For more detailed insights, you can check Kailua-Kona weather in January.

September typically brings warmer temperatures, with average highs around 28°C (82°F) and high humidity at 82%. It’s a month characterized by significant rainfall, totaling 286 mm (11.3 in) across 28 days. In contrast, February tends to be cooler, with average temperatures of 21°C (70°F) and maximums reaching 25°C (78°F). Precipitation is notably lower in February, at 149 mm (5.9 in) over 17 days, and humidity is slightly less at 79%. For more detailed insights, you can check Kailua-Kona weather in February.

September and March exhibit notable differences in weather patterns. September typically offers warmer temperatures, with minimums around 20°C (68°F) and maximums reaching up to 28°C (82°F), while March's temperatures range from a minimum of 17°C (63°F) to a maximum of 25°C (78°F). Additionally, September experiences significantly more rainfall, averaging 286 mm (11.3 in) over 28 days compared to March's 129 mm (5.1 in) over just 20 days. Humidity levels are also slightly higher in September at 82%, while March maintains a comfortable 77%. For a detailed look at what to expect, check out Kailua-Kona weather in March.

When comparing the weather in September and April, September tends to be warmer, with average temperatures reaching 24°C (75°F) and maximums of up to 28°C (82°F), while April sees slightly cooler averages of 22°C (71°F) and highs of 25°C (78°F). Precipitation is notably higher in September, with 286 mm (11.3 in) falling over 28 days, compared to April's 212 mm (8.4 in) over 24 days. Despite the differences in temperature and rainfall, humidity levels remain fairly comparable, hovering around 82% in September and 80% in April. For a more detailed look at the weather specifics in April, you can check Kailua-Kona weather in April.

When comparing the weather in September and May, we notice some intriguing similarities and differences. September features slightly warmer temperatures, with an average of 24°C (75°F) and a maximum of 28°C (82°F), compared to May's average of 22°C (72°F) and max of 26°C (79°F). Both months experience considerable rainfall, with September receiving around 286 mm (11.3 in) and May slightly wetter at 331 mm (13.1 in), though both share the same number of precipitation days at 28. Humidity levels are quite similar as well, with September at 82% and May at 80%. For a more detailed look at weather conditions, check out Kailua-Kona weather in May.

When comparing the weather in September and June, we observe some notable similarities and differences. Both months boast minimum temperatures of 20°C (68°F) and high humidity levels of 82%. However, September tends to be slightly warmer on average, with temperatures reaching up to 28°C (82°F) compared to June's maximum of 26°C (80°F). Precipitation is also a factor: September receives around 286 mm (11.3 in) over 28 days, while June is wetter with 365 mm (14.4 in) across 29 days. For more detailed information on June weather, check out Kailua-Kona weather in June.

When comparing the weather between September and July, we see that both months experience similar minimum temperatures, with September averaging a slightly warmer maximum of 28°C (82°F) compared to July's 27°C (81°F). However, July tends to have more overall precipitation, totaling 387 mm (15.2 in) over 30 days, compared to September's 286 mm (11.3 in) over 28 days. Humidity levels remain relatively high in both months, with July at 83% and September at 82%. For those looking for more information on July weather, you can visit Kailua-Kona weather in July.

In comparing the weather of September and August, both months experience similar average temperatures, hovering around 24°C (75°F) with maximums reaching 28°C (82°F) in September and 28°C (83°F) in August. However, September tends to be slightly cooler, with a minimum temperature of 20°C (68°F) compared to August's 21°C (70°F). Precipitation is significantly less in September, with 286 mm (11.3 in) over 28 days, compared to August’s 458 mm (18.0 in) across 30 days, highlighting that September is generally a drier month. Humidity levels are also marginally lower in September at 82% versus 84% in August. For more information on the weather specifics, you can check Kailua-Kona weather in August.

September and October exhibit similar temperatures, with September experiencing slightly higher averages—24°C (75°F) compared to October’s 23°C (75°F). Both months have a minimum temperature of 20°C (68°F), but September tends to reach a maximum of 28°C (82°F), while October peaks at 27°C (81°F). Rainfall decreases from September’s notable 286 mm (11.3 in) over 28 days to 230 mm (9.0 in) across 26 days in October, indicating a shift towards drier weather. Humidity remains relatively consistent, with September at 82% and October slightly higher at 83%. For more detailed information, visit Kailua-Kona weather in October.

September and November in Kailua-Kona present a noticeable shift in weather patterns. September experiences slightly warmer temperatures, with a minimum of 20°C (68°F) and a maximum of 28°C (82°F), while November sees slightly cooler temperatures, ranging from a minimum of 19°C (66°F) to a maximum of 26°C (80°F). Precipitation also differs significantly; September receives a much higher total of 286 mm (11.3 in) over 28 days, compared to November's 143 mm (5.6 in) across 20 days. Despite the slight drop in temperature, November maintains a similar humidity level at 83%, only marginally higher than September's 82%. For more detailed information, check out Kailua-Kona weather in November.

In comparing the weather between September and December, we find that September features slightly warmer temperatures, with average highs reaching 28°C (82°F) compared to December's maximum of 26°C (80°F). Both months experience high humidity, with September at 82% and December just a notch lower at 81%. Precipitation is more prevalent in September, totaling 286 mm (11.3 in) over 28 days, while December sees less rainfall at 188 mm (7.4 in) across 22 days. For those looking for more detailed information, you can check Kailua-Kona weather in December.

Compare Kailua-Kona's Climate with Cities Worldwide

Conclusion: What to Expect From September Weather in Kailua-Kona

As September rolls into Kailua-Kona, the scene shifts to a month marked by higher rainfall and humidity compared to the summer months. The warm average temperatures create a cozy atmosphere, perfect for enjoying the beautiful beaches, but the increased precipitation may prompt more indoor activities. With about 28 days of rain, it's a reminder of the lush landscapes that define this island paradise. This unique weather pattern sets September apart, inviting visitors to experience the vibrant beauty of Kailua-Kona in a different light. For those intrigued by weather trends, further details can be found here: Kailua-Kona Climate.