September Weather in Rottnest Island, Australia

Last updated: February 25, 2025

September on Rottnest Island, Australia, offers a delightful transition into spring, characterized by an average temperature of 16°C (62°F), with a comfortable maximum reaching 24°C (75°F) and a cooler minimum of 10°C (50°F). Visitors can expect mild but slightly humid conditions, with humidity levels around 71%. With 49 mm (1.9 in) of precipitation spread over 10 days, occasional rain showers are likely, making it essential to pack an umbrella while exploring the island’s stunning landscapes. Overall, September is a month of refreshing breezes and blossoming nature, perfect for outdoor activities and experiencing the unique charm of Rottnest Island.

September Temperature in Rottnest Island

In September, Rottnest Island experiences a gentle transition from the cool grip of winter to the warmth of spring. With minimum temperatures settling around 10°C (50°F) and a pleasant average of 16°C (62°F), this month offers inviting days for outdoor enthusiasts. The maximum temperature can rise to a delightful 24°C (75°F), perfectly balancing the mildness of early spring. As the island shakes off the chill from August, visitors can enjoy increasingly comfortable weather, making it an ideal time for beach strolls and exploring its stunning landscapes. The gradual warming trend hints at the glorious summer that lies just ahead.

September Weather in Rottnest Island: Daily Temperature Highs, Lows, and Averages

The chart illustrates September temperature patterns in Rottnest Island, showcasing daily minimum, maximum, and average temperatures. It highlights the typical range of temperatures throughout the month, providing insights into weather trends.
JanFebMarAprMayJunJulAugSepOctNovDec717272696563626061636670
Data source: Temperature data for Rottnest Island 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 Rottnest Island

In September, Rottnest Island experiences a significant shift in its climate as the dry season approaches. With 49 mm (1.9 in) of precipitation over 10 days, the island transitions into spring, showcasing a moderate rainfall pattern that falls in line with the overall trend of decreasing moisture levels leading into the summer months. Comparatively, this month mirrors the precipitation amount of October, both receiving equivalent totals, yet highlights a notable decrease from the heavier rains of winter, with June and July recording 158 mm (6.2 in) and 143 mm (5.6 in), respectively. The drop in rainfall, alongside fewer rainy days than July and August, emphasizes a gradual move towards drier conditions, making September an invigorating time to explore the island's natural beauty.

September Precipitation Trends in Rottnest Island

The chart displays monthly precipitation patterns in Rottnest Island, 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.
JanFebMarAprMayJunJulAugSepOctNovDec36621925801581431384949278
Data source: Precipitation data for September generated using information from the Copernicus Climate Change Service.
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September Humidity in Rottnest Island

In September, Rottnest Island enjoys a relative decrease in humidity, averaging 71%, reflecting a slight dip from the 77% and 75% levels experienced during the peak winter months of July and August. This transition marks a gradual shift toward the approaching warmer months, as humidity steadily recedes from its yearly high of 77%, signaling the onset of spring. Interestingly, September's humidity remains elevated compared to the earlier months of the year, suggesting that while the island begins to warm up, it retains a hint of the cooler season's moisture. As October approaches, humidity is expected to drop further, aligning with the island's typical climatic pattern that boasts refreshing breezes and comfortable weather.

September Average Humidity in Rottnest Island

This chart illustrates the average monthly humidity levels in Rottnest Island, 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.
JanFebMarAprMayJunJulAugSepOctNovDec53%55%59%70%72%77%77%75%71%63%56%53%
Data source: Humidity data for September generated using information from the Copernicus Climate Change Service.

September UV Index in Rottnest Island

As summer gives way to autumn, September in Rottnest Island sees a UV Index of 8, categorized as very high, with a burn time of just 15 minutes. This marks a slight decrease from the extreme levels observed in the earlier months, yet sun protection remains paramount. The trend shows that while the UV Index is notably lower than the peak summer months of January and February, it still warrants caution as we move towards October where values will jump back to extreme levels. With the changing seasons, residents and visitors alike should remain vigilant about sun safety throughout this transitional period. For more detailed insights, visit Rottnest Island UV Index.

Maximum UV Index Levels in Rottnest Island for September

The chart shows the monthly maximum UV Index (UVI) for Rottnest Island 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.
JanFebMarAprMayJunJulAugSepOctNovDec141411964468111314
Data source: Rottnest Island 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 Rottnest Island

As the crispness of autumn begins to settle in, September on Rottnest Island welcomes an impressive 297 hours of sunshine, marking a seamless transition from the warmth of winter. While days grow shorter as the year progresses, September shines as a bridge between the fading bright days of winter and the lingering light of a vibrant spring. In a notable trend, the sunshine here experiences an upward trajectory leading into the spring months, with hours gradually increasing from the longer days of August. As October approaches with even more radiant promise at 329 hours, this picturesque island prepares to bask in the fullness of its dazzling sunlit allure, inviting both locals and visitors to revel in the enchanting beauty of the season.

Monthly Sunshine Duration in Rottnest Island: September Highlighted

The September sunshine duration represents the total number of hours Rottnest Island 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.
JanFebMarAprMayJunJulAugSepOctNovDec308h315h323h289h279h261h273h285h297h329h352h384h
Data source: Rottnest Island September Sunshine duration data generated using information from the Copernicus Climate Change Service.

Chance of Sun in Rottnest Island During September

September in Rottnest Island, Australia, offers a promising chance of sunny weather, with 69% likelihood of sunshine. This marks a notable rebound from the cooler winter months, where sun chances dip to their lowest in July at 42%. As the seasons transition, the island enjoys more sunshine, following the patterns set by the late winter months of 57% in August and stepping up towards the vibrant summer months ahead, where December peaks at 80%. This trend, showcasing an increase in sunny days through September, makes it an appealing choice for visitors looking to bask in the Australian sun as spring unfolds.

Percentage of Sunny Days in September in Rottnest Island

The chart illustrates the percentage of sunny days in Rottnest Island 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 Rottnest Island experiences clear skies throughout the year.
JanFebMarAprMayJunJulAugSepOctNovDec72%72%61%54%43%52%42%57%69%51%67%80%
Data source: Rottnest Island September chance of sun data, generated using information from the Copernicus Climate Change Service.

Daylight Hours in Rottnest Island in September

As September arrives on Rottnest Island, daylight begins a subtle transition, offering 11 hours of sunshine—a slight increase compared to the 10 hours seen during the winter months of June to August. This gradual lengthening heralds the onset of spring, hinting at the brighter days ahead. Following September, daylight continues to grow, reaching 12 hours in October and culminating in a generous 14 hours by December. Overall, the progression of daylight duration throughout the year reflects a rhythmic dance with the seasons, inviting both locals and visitors to bask in the island's natural beauty as it awakens from its winter slumber.

Average Daylight Hours in Rottnest Island for September

The chart illustrates the variation in daylight duration in Rottnest Island throughout the year, with September highlighted. It shows the monthly changes in daylight hours, calculated by summing the hours between sunrise and sunset.
JanFebMarAprMayJunJulAugSepOctNovDec13h 57m13h 12m12h 14m11h 16m10h 28m10h 4m10h 16m10h 58m11h 53m12h 52m13h 44m14h 11m
Data source: Rottnest Island daylight hours, calculated by summing the hours between sunrise and sunset for each day.

September Winds in Rottnest Island

As September graces Rottnest Island, the winds begin to settle into a gentle rhythm, averaging 6.5 m/s (15 mph). This slight decrease from the bluster of July's spirited 9.3 m/s (21 mph) marks a transition into more tranquil conditions, which invite visitors to embrace the island's beauty. Although September's winds match the mild breezes of June, they are still part of a broader seasonal pattern where the warmer months typically usher in higher speeds. As October approaches, expect a modest uptick to 7.1 m/s (16 mph), continuing the island's delightful dance with the wind, blending serenity with a refreshing breeze that characterizes Rottnest Island's charm.

Average September Wind Speed in Rottnest Island

The chart displays monthly wind speed patterns in Rottnest Island, 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.
JanFebMarAprMayJunJulAugSepOctNovDec7.87.86.35.96.36.59.36.96.5 m/s7.17.17.8
Data source: Rottnest Island September wind data, generated using information from the Copernicus Climate Change Service.

How September Weather in Rottnest Island Compares to Other Months

The weather in Rottnest Island 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 Rottnest Island and find detailed weather information for every month.

September and January present quite different weather patterns. In September, temperatures range from a minimum of 10°C (50°F) to a maximum of 24°C (75°F), with an average of 16°C (62°F). The month experiences about 49 mm (1.9 in) of precipitation across approximately 10 days, alongside higher humidity levels at 71%. In contrast, January is warmer with minimum temperatures around 15°C (59°F) and maximums peaking at 29°C (85°F), averaging 22°C (71°F). This month sees significantly less rainfall, accumulating only 35 mm (1.4 in) over just 1 day, and enjoys lower humidity at 52%. For more detailed insights, you can check out the Rottnest Island weather in January.

When comparing the weather in September and February, notable differences emerge in temperature and humidity levels. September features a milder climate, with temperatures ranging from a minimum of 10°C (50°F) to a maximum of 24°C (75°F), accompanied by higher humidity at 71%. In contrast, February presents warmer conditions, with temperatures spanning from 16°C (61°F) to a sizzling 31°C (88°F) and lower humidity at 55%. Additionally, February experiences less frequent rainfall, with just 4 days of precipitation totaling 62 mm (2.5 in), compared to September's 10 days and 49 mm (1.9 in). For more information, check out Rottnest Island weather in February.

When comparing the weather in September and March, it's evident that March tends to be warmer and drier. In September, temperatures range from a minimum of 10°C (50°F) to a maximum of 24°C (75°F), with an average of 16°C (62°F) and 49 mm (1.9 in) of precipitation spread over 10 days, resulting in a humidity level of 71%. In contrast, March brings higher temperatures, with a minimum of 15°C (60°F), an average of 22°C (72°F), and a maximum of 30°C (86°F). This month experiences significantly less rainfall, totaling only 19 mm (0.7 in) over just 4 days, and a lower humidity of 59%. For more detailed information, you can check Rottnest Island weather in March.

When comparing the weather in September and April, we observe some notable differences. September tends to be cooler, with average temperatures ranging from a minimum of 10°C (50°F) to a maximum of 24°C (75°F). In contrast, April enjoys warmer temperatures, averaging between 13°C (56°F) and 27°C (81°F). While September experiences more rainfall with about 49 mm over 10 days, April is relatively drier, receiving only 25 mm of precipitation over just 3 days. Both months maintain a similar humidity level, hovering around 70-71%. For more detailed insights, you can check Rottnest Island weather in April.

In comparing the weather of September and May, both months showcase similar maximum temperatures, averaging around 24°C (75°F) to 24°C (76°F). However, September has a slightly cooler feel with a minimum temperature of 10°C (50°F), while May starts a bit warmer at 12°C (54°F). Rainfall also differs significantly, with September experiencing 49 mm (1.9 in) of precipitation compared to May's 80 mm (3.1 in), despite both months having rain on about 10 days. The humidity levels remain comparable, hovering near 71% in September and 72% in May, creating a consistently mild atmosphere. For a detailed look at the weather conditions during May, you can visit this link: Rottnest Island weather in May.

September and June exhibit notable differences in weather patterns. September tends to be slightly warmer, with average temperatures ranging from 10°C to 24°C (50°F to 75°F), while June's temperatures are slightly cooler, averaging between 11°C and 22°C (53°F to 72°F). Additionally, September experiences less precipitation, with 49 mm (1.9 in) over about 10 days, compared to June's much wetter conditions, which see 158 mm (6.2 in) over 13 days. Humidity levels also differ slightly, with June being the more humid month at 77% compared to September's 71%. For a detailed look at June weather, you can visit Rottnest Island weather in June.

In comparing the weather of September and July, we see notable differences in temperature and precipitation patterns. September features a milder climate, with minimum temperatures around 10°C (50°F) and maximums reaching 24°C (75°F), resulting in an average of 16°C (62°F). In contrast, July has slightly higher minimum temperatures at 12°C (54°F) and a lower maximum of 21°C (70°F), maintaining the same average temperature of 17°C (62°F). Additionally, July experiences significantly more precipitation, with 143 mm (5.6 in) over 19 days, compared to September's 49 mm (1.9 in) spread over just 10 days. The humidity levels also vary, being slightly higher in July at 77% versus September's 71%. For more detailed weather information specific to July, visit Rottnest Island weather in July.

In comparing the weather between September and August, September shows slightly milder conditions overall. While the average temperature remains consistent at 16°C (61°F) for both months, September experiences a maximum temperature of 24°C (75°F), making it warmer than August's maximum of 21°C (70°F). Additionally, September has lower precipitation levels, with 49 mm (1.9 in) over 10 days, compared to August's 138 mm (5.4 in) over 15 days. Humidity is also slightly reduced in September at 71%, compared to August’s 75%. For more insights on August weather, you can check Rottnest Island weather in August.

In September, temperatures range from a minimum of 10°C (50°F) to a maximum of 24°C (75°F), with an average of 16°C (62°F). The month experiences a fair amount of rain, totaling 49 mm (1.9 in) over approximately 10 days, and humidity levels are relatively high at 71%.

In contrast, October sees slightly warmer temperatures with a minimum of 11°C (52°F) and a maximum of 26°C (80°F), averaging 17°C (63°F). Precipitation remains the same at 49 mm (1.9 in), but it occurs over fewer days—just 7—and humidity decreases to a more comfortable 63%. For those interested in specific weather conditions for this period, you can learn more about Rottnest Island weather in October.

In September, the weather tends to be cooler with temperatures ranging from a minimum of 10°C (50°F) to a maximum of 24°C (75°F), averaging around 16°C (62°F). This month also sees a higher precipitation total of 49 mm (1.9 in) spread over about 10 days, accompanied by higher humidity levels of 71%. In contrast, November experiences warmer temperatures with a minimum of 13°C (55°F) and a maximum of 27°C (82°F), averaging 19°C (66°F). Precipitation drops significantly to 27 mm (1.1 in) over just 3 days, and the humidity decreases to 56%. For more specific information on weather patterns during this month, check out Rottnest Island weather in November.

In comparing the weather between September and December, one can observe a notable shift in temperature and precipitation patterns. September features a milder climate with temperatures ranging from a chilly minimum of 10°C (50°F) to a comfortable maximum of 24°C (75°F), accompanied by 49 mm (1.9 in) of precipitation spread over 10 days, resulting in a humidity level of 71%. In contrast, December brings warmer conditions, with temperatures reaching a minimum of 14°C (58°F) and potentially soaring to a maximum of 31°C (88°F). Interestingly, December experiences significantly less precipitation, totaling just 8 mm (0.3 in) over only 2 days, and a lower humidity of 53%. For more details on the weather during this month, you can visit Rottnest Island weather in December.

Compare Rottnest Island's Climate with Cities Worldwide

Conclusion: What to Expect From September Weather in Rottnest Island

As September graces Rottnest Island, the transition from winter to spring brings a delightful change in weather. With pleasant temperatures averaging around 16°C (62°F), this month offers a refreshing break from the cooler months, while still inviting crisp mornings with lows dipping to 10°C (50°F). Unlike the drier summer months, September sees a bit more humidity at 71%, along with occasional showers totaling about 49 mm (1.9 in) across roughly 10 days. This blend of warmth and mild precipitation paints a picturesque backdrop for outdoor adventures, making September an ideal time to explore the island's vibrant flora and fauna. For a deeper understanding of what to expect year-round, be sure to check out Rottnest Island Climate.