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September Weather in Redmond, United States

Last updated: June 24, 2025

In September, the average temperature in Redmond, United States hovers around 16°C (62°F). Expect a range from a chilly -9°C (15°F) to a warm 33°C (92°F). Precipitation is light, with about 21 mm (0.8 in) expected over 3 days, and the air maintains an average humidity of 47%.

September Temperature in Redmond

In September in Redmond, the average temperature is 16°C (62°F). Maximum temperatures can reach up to 33°C (92°F), while minimums can drop as low as -9°C (15°F). Be prepared for a wide range of temperatures if you're planning to travel during this time!

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

The chart illustrates September temperature patterns in Redmond, showcasing daily minimum, maximum, and average temperatures. It highlights the typical range of temperatures throughout the month, providing insights into weather trends. In Redmond, September typically has an average temperature of 16°C (62°F), with highs reaching up to 33°C (92°F) and lows dropping to around -9°C (15°F).
JanFebMarAprMayJunJulAugSepOctNovDec232533425266737161443625
Data source: Temperature data for Redmond 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 Redmond

In Redmond in September, the precipitation amount is 21 mm (0.8 in) over a period of 3 days.

September Precipitation Trends in Redmond

The chart displays monthly precipitation patterns in Redmond, 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 Redmond, September typically receives around 21 mm (0.8 inches) of precipitation spread over approximately 3 days.
JanFebMarAprMayJunJulAugSepOctNovDec39495038419151321332538
Data source: Precipitation data for September generated using information from the Copernicus Climate Change Service.
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September Humidity in Redmond

In Redmond in September, humidity is 47%. With an average temperature of 16°C (62°F), this humidity feels like a refreshing, cool breeze that invigorates your senses, making it an ideal environment for exploring and enjoying outdoor activities without feeling overly sticky or uncomfortable.

September Average Humidity in Redmond

This chart illustrates the average monthly humidity levels in Redmond, 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 Redmond is approximately 47%, offering insight into how humid the weather typically is during this month.
JanFebMarAprMayJunJulAugSepOctNovDec88%88%77%70%54%45%37%34%47%67%82%87%
Data source: Humidity data for September generated using information from the Copernicus Climate Change Service.

September UV Index in Redmond

In Redmond in September, the maximum UV index reaches 10, which corresponds to a very high Exposure Category. With a time to burn of just 15 minutes, it's crucial to take precautions. For more detailed information, you can check the Hourly UV Index in Redmond.

Maximum UV Index Levels in Redmond for September

The chart shows the monthly maximum UV Index (UVI) for Redmond 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 Redmond typically reaches 10, which falls under the very high exposure category.
JanFebMarAprMayJunJulAugSepOctNovDec479111112121110764
Data source: Redmond 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 Redmond Compares to Other Months

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

This table compares monthly weather conditions in Redmond, showing how September’s temperature, precipitation, humidity, and UV index levels differ from those of other months.
 TemperaturePrecipitationHumidityUV
January Weather-5°C (24°F)39 mm (1.5 inches)87%moderate
February Weather-4°C (26°F)49 mm (1.9 inches)88%high
March Weather1°C (33°F)50 mm (2.0 inches)77%very high
April Weather6°C (43°F)38 mm (1.5 inches)69%extreme
May Weather11°C (53°F)41 mm (1.6 inches)54%extreme
June Weather19°C (67°F)9 mm (0.3 inches)45%extreme
July Weather23°C (73°F)15 mm (0.6 inches)37%extreme
August Weather22°C (71°F)13 mm (0.5 inches)34%extreme
September Weather16°C (62°F)21 mm (0.8 inches)47%very high
October Weather7°C (44°F)33 mm (1.3 inches)67%high
November Weather2°C (37°F)25 mm (1.0 inches)82%high
December Weather-4°C (25°F)38 mm (1.5 inches)87%moderate

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