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September Weather in Walla Walla, Australia

Last updated: August 22, 2025

In September, the average temperature in Walla Walla, Australia reaches a comfortable 11°C (52°F). Expect a minimum temperature of -2°C (29°F) and a maximum of 28°C (82°F), showcasing a wide range of weather. With 45 mm (1.8 in) of precipitation over 8 days, it's wise to be prepared for some rain. Additionally, the average humidity sits at a moderate 72%, creating a potentially pleasant atmosphere for outdoor activities.

September Temperature in Walla Walla

In September in Walla Walla, the average temperature is 11°C (52°F), with maximums reaching up to 28°C (82°F) and minimums dropping as low as -2°C (29°F). This variation in temperature makes Walla Walla an interesting destination for travelers, offering a mix of pleasant and chilly weather to experience.

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

The chart illustrates September temperature patterns in Walla Walla, showcasing daily minimum, maximum, and average temperatures. It highlights the typical range of temperatures throughout the month, providing insights into weather trends. In Walla Walla, September typically has an average temperature of 11°C (52°F), with highs reaching up to 28°C (82°F) and lows dropping to around -2°C (29°F).
JanFebMarAprMayJunJulAugSepOctNovDec777369605246464752596572
Data source: Temperature data for Walla Walla 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 Walla Walla

In Walla Walla in September, the precipitation amount is 45 mm (1.8 in) over the course of 8 days.

September Precipitation Trends in Walla Walla

The chart displays monthly precipitation patterns in Walla Walla, 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 Walla Walla, September typically receives around 45 mm (1.8 inches) of precipitation spread over approximately 8 days.
JanFebMarAprMayJunJulAugSepOctNovDec362855445355626245638249
Data source: Precipitation data for September generated using information from the Copernicus Climate Change Service.
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September Humidity in Walla Walla

In Walla Walla in September, humidity is 72%. With an average temperature of 11°C (52°F), this humidity feels like a damp chill that can make outdoor activities uncomfortable, often leaving travelers feeling slightly cold and clammy unless they are dressed in layers.

September Average Humidity in Walla Walla

This chart illustrates the average monthly humidity levels in Walla Walla, 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 Walla Walla is approximately 72%, offering insight into how humid the weather typically is during this month.
JanFebMarAprMayJunJulAugSepOctNovDec42%51%60%68%76%81%83%78%72%57%53%51%
Data source: Humidity data for September generated using information from the Copernicus Climate Change Service.

September UV Index in Walla Walla

In Walla Walla 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 Walla Walla.

Maximum UV Index Levels in Walla Walla for September

The chart shows the monthly maximum UV Index (UVI) for Walla Walla 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 Walla Walla typically reaches 7, which falls under the high exposure category.
JanFebMarAprMayJunJulAugSepOctNovDec141312853357101214
Data source: Walla Walla 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 Walla Walla Compares to Other Months

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

This table compares monthly weather conditions in Walla Walla, showing how September’s temperature, precipitation, humidity, and UV index levels differ from those of other months.
 TemperaturePrecipitationHumidityUV
January Weather25°C (77°F)36 mm (1.4 inches)42%extreme
February Weather23°C (73°F)28 mm (1.1 inches)51%extreme
March Weather21°C (69°F)55 mm (2.2 inches)59%extreme
April Weather16°C (61°F)44 mm (1.7 inches)68%very high
May Weather11°C (52°F)53 mm (2.1 inches)76%moderate
June Weather8°C (46°F)55 mm (2.2 inches)81%moderate
July Weather8°C (46°F)62 mm (2.5 inches)83%moderate
August Weather8°C (47°F)62 mm (2.4 inches)78%moderate
September Weather11°C (52°F)45 mm (1.8 inches)72%high
October Weather15°C (59°F)63 mm (2.5 inches)57%very high
November Weather18°C (65°F)82 mm (3.2 inches)53%extreme
December Weather22°C (72°F)49 mm (1.9 inches)51%extreme

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