September Weather in Hilo, United States

Last updated: February 24, 2025

In September, Hilo, United States experiences a temperate climate, characterized by an average temperature of 24°C (76°F), with daily highs reaching up to 28°C (82°F) and lows around 21°C (71°F). This month sees significant precipitation, totaling 108 mm (4.3 in) over approximately 24 days, contributing to the region's lush greenery. The humidity remains high, averaging 82%, creating a tropical atmosphere that is both warm and refreshing. Visitors can expect a mix of sunshine and rain, ideal for enjoying the natural beauty that Hilo offers.

September Temperature in Hilo

In September, Hilo greets visitors with a warm embrace, as temperatures hold steady with a minimum of 21°C (71°F) and an average around 24°C (76°F). The highs reach up to 28°C (82°F), marking a slight transition into the cooler months ahead. This month reflects a trend of increasing warmth that began in July, where both the minimum and maximum temperatures started to rise, peaking in August. As September unfolds, the days are still balmy, but hints of the cooler autumn air are just around the corner, making this a delightful time for exploring the lush landscapes that surround the town. The enchanting blend of tropical warmth and the gentle breeze creates a perfect backdrop for outdoor adventures.

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

The chart illustrates September temperature patterns in Hilo, showcasing daily minimum, maximum, and average temperatures. It highlights the typical range of temperatures throughout the month, providing insights into weather trends.
JanFebMarAprMayJunJulAugSepOctNovDec707070717273747575757371
Data source: Temperature data for Hilo 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 Hilo

In September, Hilo experiences a significant dip in precipitation, receiving 108 mm (4.3 in) of rain over the month, making it one of the driest months in the annual cycle. This decline in rainfall is mirrored by the number of precipitation days, totaling 24, which is slightly less than the previous months of August (27 days) and July (28 days). While Hilo is known for its lush, tropical climate, September's weather hints at the transition toward a drier period, with a noticeable reduction in both amount and frequency of rain compared to the peak summer months. This trend sets the stage for the approaching fall, where rainfall begins to pick up again as the year draws to a close.

September Precipitation Trends in Hilo

The chart displays monthly precipitation patterns in Hilo, 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.
JanFebMarAprMayJunJulAugSepOctNovDec158262225195166107131197109189153228
Data source: Precipitation data for September generated using information from the Copernicus Climate Change Service.
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September Humidity in Hilo

In Hilo, September marks a slight dip in humidity, averaging 82%. This month follows a trend of increasing moisture during the summer, peaking in August at 84%. From June onward, a gradual rise in humidity is evident, with the figures hovering consistently between 80% and 84%. The overall pattern shows that Hilo experiences its highest humidity levels during the warm summer months, with values tapering off as autumn approaches. Despite the decrease in September, the humidity remains noticeably high, contributing to the lush, tropical landscape that Hilo is renowned for.

September Average Humidity in Hilo

This chart illustrates the average monthly humidity levels in Hilo, 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 Hilo

In September, Hilo experiences an UV Index of 13, categorized as extreme, which means that even brief exposure can lead to skin burns in just 10 minutes. This trend of high UV levels persists throughout the summer months, peaking in July and August with an index of 14. After a dip in October, the UV Index remains consistently high as the year progresses, dipping slightly in the cooler months of November and December. It's crucial for residents and visitors alike to stay vigilant about sun protection during this time. For more detailed information, visit Hilo UV Index.

Maximum UV Index Levels in Hilo for September

The chart shows the monthly maximum UV Index (UVI) for Hilo 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: Hilo 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 Hilo

September in Hilo, United States, basks in a generous 305 hours of sunshine, continuing the trend of abundant daylight that peaks during the summer months. Following the heights of July and August, which boast impressive totals of 339 and 323 hours respectively, September offers a slight yet pleasant reduction in sunshine hours. This gradual transition suggests a shift into fall while still retaining a warmth that invites outdoor activities. As the year progresses, one can observe a steady decline in sunlight, with October already hinting at 283 hours, yet September stands out as a beautiful bridge between the vibrant summer and the cooler autumn days ahead. Embrace the lingering rays of sunshine, as they beautifully taper off into the refreshing embrace of the upcoming season.

Monthly Sunshine Duration in Hilo: September Highlighted

The September sunshine duration represents the total number of hours Hilo 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.
JanFebMarAprMayJunJulAugSepOctNovDec212h244h249h284h318h331h339h323h305h283h260h252h
Data source: Hilo September Sunshine duration data generated using information from the Copernicus Climate Change Service.

Chance of Sun in Hilo During September

When considering the likelihood of sunny weather in September in Hilo, the stats reveal a slightly above-average chance of sunshine at 43%, consistent with the warmth of summer. This figure reflects a broader trend where the chance of sunny days generally hovers between the early 40s during the months surrounding September. Notably, this month mirrors June and October, suggesting a stable pattern in sunny conditions as the year transitions from the summer months to the fall. With sunshine probabilities occasionally dipping, such as in July at 31%, September stands out as a reliable choice for those seeking pleasant weather in this lush coastal town.

Percentage of Sunny Days in September in Hilo

The chart illustrates the percentage of sunny days in Hilo 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 Hilo experiences clear skies throughout the year.
JanFebMarAprMayJunJulAugSepOctNovDec41%47%36%42%42%43%31%45%43%43%43%27%
Data source: Hilo September chance of sun data, generated using information from the Copernicus Climate Change Service.

Daylight Hours in Hilo in September

As summer gives way to autumn in Hilo, September experiences a comfortable 12 hours of daylight, reflecting a gradual transition from the longer days of summer. This month parallels August in daylight duration, marking the end of the peak summer brightness, which reached 13 hours in June and July. Following September, daylight begins to wane, with October witnessing a slight decrease. This ebbing light signals the approach of winter, where daylight dips to about 11 hours in November and ultimately to 10 hours in December. Overall, the trend from the peak summer months to the shorter fall days illustrates Hilo's unique climate, where variations in daylight are subtle yet impactful.

Average Daylight Hours in Hilo for September

The chart illustrates the variation in daylight duration in Hilo throughout the year, with September highlighted. It shows the monthly changes in daylight hours, calculated by summing the hours between sunrise and sunset.
JanFebMarAprMayJunJulAugSepOctNovDec11h 4m11h 29m12h 2m12h 36m13h 4m13h 17m13h 10m12h 45m12h 12m11h 39m11h 10m10h 56m
Data source: Hilo daylight hours, calculated by summing the hours between sunrise and sunset for each day.

September Winds in Hilo

In September, Hilo experiences a gentle breeze with an average wind speed of 2.6 m/s (6 mph), marking it as one of the calmest months of the year. As the summer winds begin to wane, this slight decrease from the preceding months creates a serene atmosphere, perfect for outdoor activities and appreciating the natural beauty of the region. Notably, September's winds contrast with the slight uptick seen in November and December, where the speeds return to a more robust pace. Overall, September stands out as a tranquil period in Hilo, making it an ideal time for leisurely pursuits amidst the lush landscapes of Hawaii.

Average September Wind Speed in Hilo

The chart displays monthly wind speed patterns in Hilo, 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.
JanFebMarAprMayJunJulAugSepOctNovDec2.93.33.53.13.32.93.02.92.6 m/s2.73.13.4
Data source: Hilo September wind data, generated using information from the Copernicus Climate Change Service.

How September Weather in Hilo Compares to Other Months

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

In September, Hilo experiences warmer temperatures with a minimum of 21°C (71°F) and an average of 24°C (76°F), reaching a maximum of 28°C (82°F). The month also sees significant rainfall, with 108 mm (4.3 in) spread over 24 days and a humidity level of 82%. In contrast, January features slightly cooler temperatures, with a minimum of 18°C (65°F) and an average of 21°C (71°F), peaking at 25°C (77°F). Precipitation increases to 158 mm (6.2 in) over 20 days, but the humidity is a bit lower at 79%. For more details on the weather specifics in January, you can visit Hilo weather in January.

September and February exhibit distinct weather patterns. In September, the temperatures are generally warmer, with minimums around 21°C (71°F) and maximums peaking at 28°C (82°F). The average temperature is 24°C (76°F), accompanied by moderate rainfall of 108 mm (4.3 in) over 24 days, and humidity levels are relatively high at 82%. In contrast, February sees slightly cooler temperatures, with minimums dropping to 17°C (62°F) and maximums reaching 26°C (79°F), resulting in an average of 21°C (70°F). However, February is notably wetter, with a total precipitation of 262 mm (10.3 in) spread across 23 days, while humidity remains a bit lower at 79%. For a more detailed perspective on February weather in Hilo, check out Hilo weather in February.

When comparing the weather in September and March, September tends to be warmer with average temperatures between 21°C (71°F) and 28°C (82°F), while March offers slightly cooler conditions with an average range of 17°C (64°F) to 26°C (78°F). In terms of precipitation, March experiences significantly more rainfall, with 225 mm (8.8 in) over 26 days compared to September's 108 mm (4.3 in) over 24 days. Interestingly, despite the increased precipitation in March, the humidity levels are slightly lower at 77% compared to September's 82%. For a more detailed look at March's climate, check out Hilo weather in March.

In comparing the weather of September and April, September tends to be warmer with average temperatures ranging from a minimum of 21°C (71°F) to a maximum of 28°C (82°F), whereas April's temperatures are slightly cooler, with a range of 18°C (65°F) to 26°C (80°F). Precipitation levels are also noteworthy; September experiences 108 mm (4.3 in) of rain over 24 days, while April sees significantly higher rainfall at 195 mm (7.7 in) across 25 days. Humidity levels are quite similar, with September at 82% and April at 80%. For a more detailed look at April weather conditions, you can check Hilo weather in April.

Comparing the weather in September and May reveals some notable differences, particularly in temperature and precipitation. In September, temperatures range from a minimum of 21°C (71°F) to a maximum of 28°C (82°F), with an average of 24°C (76°F). Conversely, May sees slightly cooler temperatures, with a minimum of 19°C (67°F), an average of 22°C (73°F), and a maximum of 26°C (79°F). When it comes to precipitation, September experiences 108 mm (4.3 in) over 24 days, while May has significantly higher rainfall at 166 mm (6.5 in) across 27 days. Humidity levels are relatively similar, at 82% in September and 80% in May. For further details on May's weather, you can visit Hilo weather in May.

In comparing the weather of September and June, we find that both months exhibit warm temperatures and high humidity, with September slightly warmer overall. September features a minimum temperature of 21°C (71°F), an average of 24°C (76°F), and a maximum of 28°C (82°F), while June offers a minimum of 20°C (69°F), an average of 23°C (74°F), and a maximum of 27°C (80°F). Precipitation levels are quite similar as well, with September receiving 108 mm (4.3 in) over 24 days, compared to June's 106 mm (4.2 in) across 25 days. Notably, both months maintain a humidity level of 82%, creating a consistently tropical atmosphere. For more detailed information, you can check out Hilo weather in June.

In comparing the weather of September and July, we see some notable similarities and differences. Both months maintain a minimum temperature of 21°C (70-71°F) and an average around 24°C (75-76°F). However, July tends to be slightly warmer, with a maximum temperature of 29°C (85°F) compared to September's 28°C (82°F). Precipitation is more frequent in July, occurring on 28 days with a total of 131 mm (5.1 in), whereas September experiences rainfall on 24 days, totaling 108 mm (4.3 in). Humidity levels are quite close, with September at 82% and July at 83%. For more details on July's weather specifically, you can refer to Hilo weather in July.

In comparing the weather of September and August, both months exhibit relatively warm temperatures, with September showing a slight increase in maximum temperature at 28°C (82°F) compared to August's 27°C (82°F). However, September is marked by lower overall precipitation, recording 108 mm (4.3 in) over 24 days, while August experiences more rainfall at 197 mm (7.8 in) over 27 days. Humidity levels remain high in both months, with September at 82% and August slightly higher at 84%. For more detailed insights on August weather in Hilo, you can refer to Hilo weather in August.

In September, the weather remains warm with average temperatures hovering around 24°C (76°F) and maximums reaching 28°C (82°F). However, this month experiences a notable amount of precipitation, totaling 108 mm (4.3 in) over 24 days, coinciding with relatively high humidity levels at 82%.

By October, temperatures slightly vary, with a minimum of 20°C (69°F) and the same average of 24°C (75°F) as in September. However, October sees an increase in rainfall, with precipitation soaring to 189 mm (7.4 in) over just 23 days, and humidity rising to 83%. For a more detailed look at the weather in October, you can check Hilo weather in October.

In September, the weather tends to be slightly warmer, with temperatures averaging around 24°C (76°F) and reaching highs of 28°C (82°F). However, it usually experiences less rainfall, with a total precipitation of 108 mm (4.3 in) over 24 days. In contrast, November sees a slight drop in temperature, averaging 23°C (74°F) with maximums of 27°C (80°F), but it brings increased rainfall, totaling 153 mm (6.0 in) over the same duration. Humidity remains quite similar in both months, hovering around 82% in September and 83% in November. For more detailed information, check out Hilo weather in November.

September and December in Hilo exhibit noteworthy differences in weather patterns. September typically showcases warmer temperatures, with highs around 28°C (82°F) and an average of 24°C (76°F), while December's temperatures are a bit cooler, peaking at 26°C (78°F) with an average of 22°C (71°F). Both months experience considerable rainfall, but December sees a significant increase in precipitation, with 228 mm (9.0 in) compared to September's 108 mm (4.3 in), leading to a wetter atmosphere despite similar humidity levels around 81-82%. For more detailed information on December weather, you can refer to Hilo weather in December.

Compare Hilo's Climate with Cities Worldwide

Conclusion: What to Expect From September Weather in Hilo

As September embraces Hilo, it brings a unique blend of warmth and moisture that stands apart from other months. With an average temperature hovering around 24°C (76°F), visitors can expect pleasant conditions, though the humidity often climbs to a notable 82%. This month is characterized by frequent rainfall, averaging 108 mm over 24 days, which contributes to Hilo’s lush landscape. While other months may offer drier spells, September's wet embrace serves as a reminder of the island's vibrant ecosystem. For a deeper dive into the subtleties of Hilo's climate, check out Hilo Climate.