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September Weather in Spokane Valley, United States

Last updated: June 24, 2025

In September, the average temperature in Spokane Valley, United States hovers around 16°C (62°F). Expect a minimum of 2°C (35°F) and a maximum reaching up to 35°C (95°F). With an average precipitation of 35 mm (1.4 in) over 5 days, and a humidity level of 62%, it's a month that blends mild warmth with periodic moisture.

September Temperature in Spokane Valley

In September in Spokane Valley, the average temperature is 16°C (62°F), with maximums reaching up to 35°C (95°F) and minimums dropping as low as 2°C (35°F). This variation makes it essential for travelers to pack accordingly for a range of temperatures.

September Weather in Spokane Valley: Daily Temperature Highs, Lows, and Averages

The chart illustrates September temperature patterns in Spokane Valley, showcasing daily minimum, maximum, and average temperatures. It highlights the typical range of temperatures throughout the month, providing insights into weather trends. In Spokane Valley, September typically has an average temperature of 16°C (62°F), with highs reaching up to 35°C (95°F) and lows dropping to around 2°C (35°F).
JanFebMarAprMayJunJulAugSepOctNovDec303039465765747361473832
Data source: Temperature data for Spokane Valley 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 Spokane Valley

In Spokane Valley in September, the precipitation amount is 35 mm (1.4 in) over a span of 5 days.

September Precipitation Trends in Spokane Valley

The chart displays monthly precipitation patterns in Spokane Valley, 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 Spokane Valley, September typically receives around 35 mm (1.4 inches) of precipitation spread over approximately 5 days.
JanFebMarAprMayJunJulAugSepOctNovDec82746560532441035628883
Data source: Precipitation data for September generated using information from the Copernicus Climate Change Service.
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September Humidity in Spokane Valley

In Spokane Valley in September, humidity is 62%. With an average temperature of 16°C (62°F), this humidity feels like a damp blanket wrapping around you, making outdoor activities a bit sticky but still comfortable if you plan to explore at a leisurely pace.

September Average Humidity in Spokane Valley

This chart illustrates the average monthly humidity levels in Spokane Valley, 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 Spokane Valley is approximately 62%, offering insight into how humid the weather typically is during this month.
JanFebMarAprMayJunJulAugSepOctNovDec89%89%87%84%78%78%77%64%62%79%87%90%
Data source: Humidity data for September generated using information from the Copernicus Climate Change Service.

September UV Index in Spokane Valley

In Spokane Valley 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 Spokane Valley.

Maximum UV Index Levels in Spokane Valley for September

The chart shows the monthly maximum UV Index (UVI) for Spokane Valley 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 Spokane Valley typically reaches 7, which falls under the high exposure category.
JanFebMarAprMayJunJulAugSepOctNovDec2456891097532
Data source: Spokane Valley 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 Spokane Valley Compares to Other Months

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

This table compares monthly weather conditions in Spokane Valley, showing how September’s temperature, precipitation, humidity, and UV index levels differ from those of other months.
 TemperaturePrecipitationHumidityUV
January Weather-1°C (30°F)82 mm (3.2 inches)89%low
February Weather-1°C (30°F)74 mm (2.9 inches)89%moderate
March Weather4°C (39°F)65 mm (2.6 inches)87%moderate
April Weather8°C (47°F)60 mm (2.4 inches)84%high
May Weather14°C (57°F)53 mm (2.1 inches)77%very high
June Weather19°C (66°F)24 mm (0.9 inches)78%very high
July Weather23°C (74°F)4 mm (0.2 inches)77%very high
August Weather23°C (73°F)10 mm (0.4 inches)64%very high
September Weather16°C (62°F)35 mm (1.4 inches)62%high
October Weather8°C (47°F)62 mm (2.4 inches)79%moderate
November Weather3°C (38°F)88 mm (3.5 inches)87%moderate
December Weather0°C (32°F)83 mm (3.2 inches)90%low

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