September Weather in Avarua, Cook Islands

Last updated: August 21, 2025

In September, Avarua, located in the stunning Cook Islands, experiences a delightful tropical climate marked by pleasantly warm temperatures. Daily maximums reach around 25°C (78°F), while the average temperature hovers at a comfortable 23°C (74°F), cooling down to a minimum of 19°C (66°F) at night. Although this month sees around 64 mm (2.5 in) of rainfall spread across approximately 10 days, the high humidity level of 82% transforms the air into a refreshing embrace, making it an ideal time for both relaxation and exploration. Embrace the beauty of Avarua in September, where the warmth of the sun meets the calming whispers of the ocean.

September Temperature in Avarua

September in Avarua, Cook Islands, marks the transition into spring with pleasantly mild temperatures. The month features a minimum temperature of 19°C (66°F), an average of 23°C (74°F), and a maximum of 25°C (78°F). This slight warming trend from the cooler winter months of July and August offers visitors a delightful climate to explore the island's natural beauty. As the temperatures steadily transition upwards, September serves as a gentle reminder of the vibrant summer ahead, making it an ideal time to enjoy the picturesque landscapes and rich culture of this tropical paradise.

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

The chart illustrates September temperature patterns in Avarua, showcasing daily minimum, maximum, and average temperatures. It highlights the typical range of temperatures throughout the month, providing insights into weather trends. In Avarua, 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).
JanFebMarAprMayJunJulAugSepOctNovDec797980797775747373747577
Data source: Temperature data for Avarua 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 Avarua

In September, Avarua experiences a noticeable drop in precipitation, with rainfall measuring just 64 mm (2.5 in) over approximately 10 days. This pattern marks a continuation of the more moderate conditions observed in the previous months of June and July, both of which are among the driest months in the year. Following the heavier downpours typical of the first half of the year, September's lighter rainfall signals a transition towards the drier season. This trend towards decreased precipitation contributes to a more pleasant atmosphere, allowing residents and visitors alike to enjoy the lush beauty of the Cook Islands with fewer rainy interruptions.

September Precipitation Trends in Avarua

The chart displays monthly precipitation patterns in Avarua, 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 Avarua, September typically receives around {2} mm ({3} inches) of precipitation spread over approximately {4} days.
JanFebMarAprMayJunJulAugSepOctNovDec168298209162165749113264122120220
Data source: Precipitation data for September generated using information from the Copernicus Climate Change Service.
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September Humidity in Avarua

September in Avarua, Cook Islands, brings a notable shift in humidity, settling at 82%. This level reflects a subtle increase from August's 80%, indicating a gradual trend toward higher moisture levels as the year progresses. While humid climates are a staple in Avarua throughout the year, September's readings contribute to a consistent pattern where humidity remains relatively high, peaking in February at 85% and slowly tapering off towards the mid-year months. This steady fluctuation not only highlights the tropical essence of the Cook Islands but also sets the stage for an inviting atmosphere as visitors experience the warm embrace of the surrounding sea.

September Average Humidity in Avarua

This chart illustrates the average monthly humidity levels in Avarua, 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 Avarua is approximately {2}%, offering insight into how humid the weather typically is during this month.
JanFebMarAprMayJunJulAugSepOctNovDec84%85%81%79%80%77%77%80%82%83%84%84%
Data source: Humidity data for September generated using information from the Copernicus Climate Change Service.

September UV Index in Avarua

In September, Avarua experiences a UV Index of 11, placing it once again in the extreme exposure category with a burn time of just 10 minutes. This month continues the trend observed earlier in the year, where exceptionally high UV levels dominate, demanding vigilance for sun protection. While the intensity decreases slightly from the height of summer, the need for caution remains critical as September transitions towards the warmer months. Visitors and locals alike should stay informed and prepared to avoid overexposure. For more insights on UV levels throughout the year, visit Avarua UV Index.

Maximum UV Index Levels in Avarua for September

The chart shows the monthly maximum UV Index (UVI) for Avarua 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 Avarua typically reaches {2}, which falls under the {3} exposure category.
JanFebMarAprMayJunJulAugSepOctNovDec161514118771011141415
Data source: Avarua 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 Avarua

As the vibrant hues of September embrace Avarua, the Cook Islands, the sun shines brightly, bringing 268 hours of glorious daylight to the paradise below. This marks a notable increase from the previous month, highlighting a gradual upward trend in sunshine that builds momentum as the year progresses. After a slight dip in sunshine hours from May to June, the warmth returns in full force, setting the stage for the lively October that promises 275 hours of sun. With each month, the consistent rise in sunlight not only enriches the island's beauty but also invites both locals and visitors to bask in the radiant warmth, celebrating the alluring clime that characterizes the Cook Islands throughout the year.

Monthly Sunshine Duration in Avarua: September Highlighted

The September sunshine duration represents the total number of hours Avarua 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.
JanFebMarAprMayJunJulAugSepOctNovDec248h249h288h254h235h237h245h258h268h275h280h284h
Data source: Avarua September Sunshine duration data generated using information from the Copernicus Climate Change Service.

Chance of Sun in Avarua During September

September in Avarua, Cook Islands, marks a delightful shift in weather, boasting a 53% chance of sunny days—the highest rate of the year. This upswing reflects a trend toward increased sunshine as the region transitions into more favorable conditions following the winter months. July and August, which are typically the cloudier months, have lower probabilities of sun at 48% and 41%, respectively. As October approaches, the likelihood of sunny weather declines slightly to 45%, but overall, September stands out as the month to embrace the sun. Whether you're lounging on the beach or exploring the vibrant local culture, this period offers an ideal backdrop for outdoor adventures under bright blue skies.

Percentage of Sunny Days in September in Avarua

The chart illustrates the percentage of sunny days in Avarua 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 Avarua experiences clear skies throughout the year.
JanFebMarAprMayJunJulAugSepOctNovDec33%27%33%43%31%42%48%41%53%45%40%26%
Data source: Avarua September chance of sun data, generated using information from the Copernicus Climate Change Service.

Daylight Hours in Avarua in September

In September, Avarua, Cook Islands, enjoys about 11 hours of daylight, a continuation of the trend observed in August. As the year progresses, daylight gradually begins to increase again, following the shorter days of June and July, which experience only 10 hours of sunlight. The daylight duration peaks at 13 hours in the summer months of January and November, providing plenty of sunshine for residents and visitors alike. Overall, September stands as a transitional month, hinting at the return of longer days as the island moves into October and beyond.

Average Daylight Hours in Avarua for September

The chart illustrates the variation in daylight duration in Avarua throughout the year, with September highlighted. It shows the monthly changes in daylight hours, calculated by summing the hours between sunrise and sunset.
JanFebMarAprMayJunJulAugSepOctNovDec13h 14m12h 45m12h 10m11h 33m11h 4m10h 50m10h 58m11h 24m11h 58m12h 35m13h 7m13h 23m
Data source: Avarua daylight hours, calculated by summing the hours between sunrise and sunset for each day.

September Winds in Avarua

In September, Avarua, Cook Islands, enjoys a delightful average wind speed of 6.6 m/s (15 mph), contributing to the region's pleasant tropical ambiance. As the winds pick up slightly from the calmer months of February and March, the conditions remain favorable for outdoor activities. This gentle breeze is consistent with the general trend observed from May through October, where average wind speeds hover between 6.0 m/s to 7.4 m/s. The winds provide a refreshing respite amid the warm island climate, making September an ideal time for sailing and exploring the natural beauty of the Cook Islands. As the seasons transition, the steady winds invite both adventure and relaxation, encapsulating the serene allure of this island paradise.

Average September Wind Speed in Avarua

The chart displays monthly wind speed patterns in Avarua, 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.
JanFebMarAprMayJunJulAugSepOctNovDec5.84.95.35.47.47.16.06.76.6 m/s6.86.36.3
Data source: Avarua September wind data, generated using information from the Copernicus Climate Change Service.

How September Weather in Avarua Compares to Other Months

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

In September, the weather is generally mild, with average temperatures ranging from a minimum of 19°C (66°F) to a maximum of 25°C (78°F). During this month, you can expect about 64 mm (2.5 inches) of precipitation spread over 10 days, accompanied by humidity levels around 82%. In contrast, January experiences warmer conditions, with temperatures ranging from a minimum of 24°C (75°F) to a maximum of 28°C (84°F). However, this month also sees increased rainfall, totaling 168 mm (6.6 inches) over 17 days, with humidity slightly higher at 84%. For more details, you can explore Avarua weather in January.

When comparing the weather in September and February, it's clear that February is significantly warmer and wetter. In September, temperatures range from a minimum of 19°C (66°F) to a maximum of 25°C (78°F), with an average of 23°C (74°F) and 64 mm (2.5 in) of precipitation over about 10 days. In contrast, February boasts higher temperatures, with a minimum of 24°C (75°F) and a maximum of 29°C (84°F), averaging 26°C (79°F). Additionally, February experiences much more rainfall, with a total of 298 mm (11.7 in) occurring over approximately 22 days. Humidity is also slightly higher in February at 85%, compared to 82% in September. For more details, check out Avarua weather in February.

In September, the weather is relatively mild with average temperatures ranging from a minimum of 19°C (66°F) to a maximum of 25°C (78°F). The month experiences about 64 mm (2.5 in) of precipitation over approximately 10 days, coupled with a humidity level of 82%.

In contrast, March is warmer, featuring average temperatures ranging from a minimum of 24°C (75°F) to a maximum of 29°C (84°F). However, it also sees significantly more rainfall, with 209 mm (8.2 in) of precipitation spread across around 24 days, while maintaining a slightly lower humidity of 81%.

For detailed weather insights, consider checking out Avarua weather in March.

In comparing the weather of September and April, it is evident that April tends to be warmer, with average temperatures ranging from a minimum of 23°C (74°F) to a maximum of 28°C (83°F), compared to September's milder range of 19°C (66°F) to 25°C (78°F). While September experiences 64 mm (2.5 in) of precipitation over approximately 10 days, April is notably wetter, with 162 mm (6.4 in) of rainfall spread over 17 days. Humidity levels are relatively similar, with September at 82% and April slightly lower at 79%, making both months feel quite humid. For more detailed insights on April weather, you can visit Avarua weather in April.

In comparing the weather of September and May, we can see notable differences in temperature and precipitation patterns. September typically experiences milder temperatures, with a minimum of 19°C (66°F) and an average of 23°C (74°F), while May is warmer, with a minimum of 22°C (71°F) and an average of 25°C (78°F). Additionally, May tends to be much wetter, receiving approximately 165 mm (6.5 in) of rainfall over 16 days compared to September's 64 mm (2.5 in) over 10 days. Though humidity levels are relatively similar, with September at 82% and May at 80%, May's warmer temperatures and higher rainfall make it feel more humid overall. For a detailed look at May weather conditions, you can visit Avarua weather in May.

In comparing the weather between September and June, September tends to be slightly cooler with an average temperature of 23°C (74°F) compared to June's average of 24°C (75°F). Both months experience a similar level of humidity, with September at 82% and June slightly lower at 77%. However, September has less rainfall, totaling 64 mm (2.5 in) over an average of 10 days, while June receives 74 mm (2.9 in) across about 12 days. For more detailed information, you can check Avarua weather in June.

In comparing the weather between September and July, we can observe some notable differences. September typically has slightly lower temperatures, with a minimum of 19°C (66°F) and a maximum of 25°C (78°F), while July features a minimum of 20°C (68°F) and a maximum of 26°C (79°F). Both months have similar average temperatures of around 23°C (74°F). However, July receives more precipitation, with 91 mm (3.6 in) over 13 days compared to September’s 64 mm (2.5 in) over 10 days. Additionally, September experiences higher humidity levels at 82%, while July has a slightly lower humidity of 77%. For more details on July weather, you can visit Avarua weather in July.

In comparing the weather between August and September, we can see some notable differences. September features slightly cooler average temperatures, with a maximum of 25°C (78°F) compared to August's peak of 26°C (79°F). Precipitation also decreases significantly from August's 132 mm (5.2 in) over 12 days to just 64 mm (2.5 in) over 10 days in September, indicating drier conditions. Humidity remains relatively high in both months, with September at 82% and August at 80%. For those interested in more details about August weather, you can check Avarua weather in August.

September and October in Avarua both feature a similar temperature profile, with minimums around 19°C (66°F), averages at 23°C (74°F), and maximums reaching 25°C (78°F). However, October experiences a notable increase in precipitation, totaling 122 mm (4.8 in) compared to September's 64 mm (2.5 in), over a slightly longer duration of 12 days of rain versus 10. Humidity remains relatively constant, with October at 83% compared to September's 82%. For a more detailed look at the weather patterns in October, check out Avarua weather in October.

September and November present a noticeable transition in weather patterns. In September, temperatures range from a minimum of 19°C (66°F) to a maximum of 25°C (78°F), with an average of 23°C (74°F). This month typically sees about 64 mm (2.5 in) of precipitation over 10 days and a humidity level of 82%. In contrast, November boasts slightly warmer temperatures, with a minimum of 21°C (71°F), an average of 24°C (76°F), and a maximum of 27°C (80°F). However, it experiences increased rainfall, totaling 120 mm (4.7 in) across 15 days, alongside a slight rise in humidity to 84%. For more details on the November weather, check Avarua weather in November.

September and December both exhibit warm weather, but December tends to be slightly hotter and wetter. In September, temperatures range from a minimum of 19°C (66°F) to a maximum of 25°C (78°F), with an average of 23°C (74°F). This month receives around 64 mm (2.5 in) of precipitation over about 10 days, alongside an average humidity of 82%.

In contrast, December sees a rise in temperatures, with minimums of 23°C (74°F) and maximums reaching 28°C (82°F), while the average remains at 25°C (78°F). This month is also significantly wetter, with precipitation totaling 220 mm (8.7 in) across 19 days, and a slightly higher humidity of 84%. For a more detailed look at December weather, check out Avarua weather in December.

Compare Avarua's Climate with Cities Worldwide

Conclusion: What to Expect From September Weather in Avarua

As September approaches in Avarua, the weather begins to exhibit a subtle transition from the cooler, drier months of winter. This month features a comfortable average temperature that hovers around the low 20s Celsius, making it an inviting time for visitors. While precipitation increases, bringing about ten rainy days, the humidity remains relatively high, creating a tropical atmosphere that can feel quite lush. The blend of moderate warmth and occasional rain distinguishes September from the dryer, less humid months that precede it, offering a unique experience for anyone exploring the beauty of the Cook Islands. For a deeper understanding of this charming climate, check out Avarua Climate.