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September Weather in Mortlake, Australia

Last updated: August 22, 2025

In September, the average temperature in Mortlake, Australia hovers around 10°C (51°F), with minimums plunging to -3°C (28°F) and maximums peaking at 26°C (78°F). Expect a moderate precipitation of 69 mm (2.7 in) spread over about 12 days, all while dealing with an average humidity of 76%. Embrace the crisp air and be prepared for the occasional rain!

September Temperature in Mortlake

In September, in Mortlake, the average temperature is 10°C (51°F). The maximum can reach 26°C (78°F), and the minimum can be as low as -3°C (28°F). This variability makes it important for travelers to pack layers to stay comfortable during their visit.

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

The chart illustrates September temperature patterns in Mortlake, showcasing daily minimum, maximum, and average temperatures. It highlights the typical range of temperatures throughout the month, providing insights into weather trends. In Mortlake, September typically has an average temperature of 10°C (51°F), with highs reaching up to 26°C (78°F) and lows dropping to around -3°C (28°F).
JanFebMarAprMayJunJulAugSepOctNovDec666463575248474851555962
Data source: Temperature data for Mortlake 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 Mortlake

In Mortlake in September, the precipitation amount is 69 mm (2.7 in) over the span of 12 days.

September Precipitation Trends in Mortlake

The chart displays monthly precipitation patterns in Mortlake, 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 Mortlake, September typically receives around 69 mm (2.7 inches) of precipitation spread over approximately 12 days.
JanFebMarAprMayJunJulAugSepOctNovDec403241516940586969747346
Data source: Precipitation data for September generated using information from the Copernicus Climate Change Service.
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September Humidity in Mortlake

In Mortlake in September, humidity is 76%. With an average temperature of 10°C (51°F), this humidity feels like a damp chill that can make outdoor excursions feel much colder, requiring extra layers for comfort as you explore the area.

September Average Humidity in Mortlake

This chart illustrates the average monthly humidity levels in Mortlake, 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 Mortlake is approximately 76%, offering insight into how humid the weather typically is during this month.
JanFebMarAprMayJunJulAugSepOctNovDec65%67%71%75%80%80%81%79%76%72%72%69%
Data source: Humidity data for September generated using information from the Copernicus Climate Change Service.

September UV Index in Mortlake

In Mortlake in September, the maximum UV index is 7, which corresponds to the high Exposure Category. This means that the time to burn is approximately 25 minutes. For more detailed information, you can check the Hourly UV Index in Mortlake.

Maximum UV Index Levels in Mortlake for September

The chart shows the monthly maximum UV Index (UVI) for Mortlake 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 Mortlake typically reaches 7, which falls under the high exposure category.
JanFebMarAprMayJunJulAugSepOctNovDec14121174335791214
Data source: Mortlake 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.

How September Weather in Mortlake Compares to Other Months

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

This table compares monthly weather conditions in Mortlake, showing how September’s temperature, precipitation, humidity, and UV index levels differ from those of other months.
 TemperaturePrecipitationHumidityUV
January Weather19°C (67°F)40 mm (1.6 inches)65%extreme
February Weather18°C (64°F)32 mm (1.2 inches)67%extreme
March Weather17°C (63°F)41 mm (1.6 inches)71%extreme
April Weather14°C (58°F)51 mm (2.0 inches)75%high
May Weather11°C (52°F)69 mm (2.7 inches)80%moderate
June Weather9°C (48°F)40 mm (1.6 inches)80%moderate
July Weather9°C (48°F)58 mm (2.3 inches)80%moderate
August Weather9°C (48°F)69 mm (2.7 inches)79%moderate
September Weather10°C (51°F)69 mm (2.7 inches)76%high
October Weather13°C (55°F)74 mm (2.9 inches)72%very high
November Weather15°C (59°F)73 mm (2.9 inches)72%extreme
December Weather17°C (62°F)46 mm (1.8 inches)69%extreme

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