nomadseason

September Weather in East Washington, United States

Last updated: June 24, 2025

In September, the average temperature in East Washington, United States is a pleasant 20°C (68°F). However, temperatures can fluctuate, with a minimum of 5°C (41°F) and a maximum reaching 34°C (94°F). Expect 124 mm (4.9 in) of rainfall spread over about 10 days, contributing to an average humidity level of 77%.

September Temperature in East Washington

In September in East Washington, the average temperature is 20°C (68°F). Maximum temperatures can reach 34°C (94°F) and minimums can drop as low as 5°C (41°F). This varied climate makes it a great time for travelers to experience both warm days and cooler evenings, perfect for outdoor activities and exploration.

September Weather in East Washington: Daily Temperature Highs, Lows, and Averages

The chart illustrates September temperature patterns in East Washington, showcasing daily minimum, maximum, and average temperatures. It highlights the typical range of temperatures throughout the month, providing insights into weather trends. In East Washington, September typically has an average temperature of 20°C (68°F), with highs reaching up to 34°C (94°F) and lows dropping to around 5°C (41°F).
JanFebMarAprMayJunJulAugSepOctNovDec323642526370757368574237
Data source: Temperature data for East Washington generated using information from the Copernicus Climate Change Service.
Choose your preferred temperature unit
The average of daily temperatures (24 hours) calculated across all days in the month.

September Precipitation in East Washington

In East Washington in September, the precipitation amount is 124 mm (4.9 in) spread over a duration of 10 days.

September Precipitation Trends in East Washington

The chart displays monthly precipitation patterns in East Washington, 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 East Washington, September typically receives around 124 mm (4.9 inches) of precipitation spread over approximately 10 days.
JanFebMarAprMayJunJulAugSepOctNovDec881211121301391471428812412288106
Data source: Precipitation data for September generated using information from the Copernicus Climate Change Service.
Choose your preferred precipitation unit

September Humidity in East Washington

In East Washington in September, humidity is 77%. With an average temperature of 20°C (68°F), this humidity feels like a warm, sticky embrace, making it essential for travelers to stay hydrated and take breaks in shaded areas to avoid feeling sluggish in the heat.

September Average Humidity in East Washington

This chart illustrates the average monthly humidity levels in East Washington, 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 East Washington is approximately 77%, offering insight into how humid the weather typically is during this month.
JanFebMarAprMayJunJulAugSepOctNovDec89%88%87%87%81%83%82%76%77%82%89%86%
Data source: Humidity data for September generated using information from the Copernicus Climate Change Service.

September UV Index in East Washington

In East Washington in September, the maximum UV index is 8, which corresponds to a very high Exposure Category. This means that the time to burn is only 15 minutes. For more detailed information, you can refer to the Hourly UV Index in East Washington.

Maximum UV Index Levels in East Washington for September

The chart shows the monthly maximum UV Index (UVI) for East Washington 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 East Washington typically reaches 8, which falls under the very high exposure category.
JanFebMarAprMayJunJulAugSepOctNovDec356910101098642
Data source: East Washington 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 East Washington Compares to Other Months

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

This table compares monthly weather conditions in East Washington, showing how September’s temperature, precipitation, humidity, and UV index levels differ from those of other months.
 TemperaturePrecipitationHumidityUV
January Weather0°C (32°F)88 mm (3.5 inches)88%moderate
February Weather2°C (36°F)121 mm (4.8 inches)88%moderate
March Weather6°C (42°F)112 mm (4.4 inches)87%high
April Weather11°C (52°F)130 mm (5.1 inches)87%very high
May Weather17°C (63°F)138 mm (5.5 inches)81%very high
June Weather21°C (70°F)147 mm (5.8 inches)83%very high
July Weather24°C (75°F)142 mm (5.6 inches)82%very high
August Weather23°C (73°F)88 mm (3.5 inches)76%very high
September Weather20°C (68°F)124 mm (4.9 inches)77%very high
October Weather14°C (58°F)122 mm (4.8 inches)82%high
November Weather6°C (43°F)88 mm (3.5 inches)89%moderate
December Weather3°C (37°F)106 mm (4.2 inches)86%low

Compare East Washington's Climate with Cities Worldwide