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September Weather in Heppner, United States

Last updated: June 24, 2025

In September, the average temperature in Heppner, United States is a mild 16°C (61°F), perfect for outdoor activities. However, temperatures can vary significantly, dipping to a chilly 0°C (32°F) and soaring as high as 35°C (96°F). Expect some light rain, with an average precipitation of 27 mm (1.1 in) over about 4 days. The climate remains comfortably humid, with an average humidity level of 58%.

September Temperature in Heppner

In September in Heppner, the average temperature is 16°C (61°F), with maximums reaching up to 35°C (96°F) and minimums dropping as low as 0°C (32°F). Travelers should be prepared for a wide range of temperatures and pack accordingly to enjoy their visit.

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

The chart illustrates September temperature patterns in Heppner, showcasing daily minimum, maximum, and average temperatures. It highlights the typical range of temperatures throughout the month, providing insights into weather trends. In Heppner, September typically has an average temperature of 16°C (61°F), with highs reaching up to 35°C (96°F) and lows dropping to around 0°C (32°F).
JanFebMarAprMayJunJulAugSepOctNovDec333339465463717161483933
Data source: Temperature data for Heppner 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 Heppner

In Heppner in September, the total precipitation amount is 27 mm (1.1 in) over a span of 4 days.

September Precipitation Trends in Heppner

The chart displays monthly precipitation patterns in Heppner, 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 Heppner, September typically receives around 27 mm (1.1 inches) of precipitation spread over approximately 4 days.
JanFebMarAprMayJunJulAugSepOctNovDec60856969472721027466561
Data source: Precipitation data for September generated using information from the Copernicus Climate Change Service.
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September Humidity in Heppner

In Heppner in September humidity is 58%. With an average temperature of 16°C (61°F), this humidity feels like a soft blanket enveloping you, making it ideal for leisurely sightseeing but slightly muggy if you're engaging in more strenuous activities.

September Average Humidity in Heppner

This chart illustrates the average monthly humidity levels in Heppner, 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 Heppner is approximately 58%, offering insight into how humid the weather typically is during this month.
JanFebMarAprMayJunJulAugSepOctNovDec86%86%85%83%77%81%77%60%58%75%85%87%
Data source: Humidity data for September generated using information from the Copernicus Climate Change Service.

September UV Index in Heppner

In Heppner 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 Heppner.

Maximum UV Index Levels in Heppner for September

The chart shows the monthly maximum UV Index (UVI) for Heppner 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 Heppner typically reaches 8, which falls under the very high exposure category.
JanFebMarAprMayJunJulAugSepOctNovDec34689101098532
Data source: Heppner 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 Heppner Compares to Other Months

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

This table compares monthly weather conditions in Heppner, showing how September’s temperature, precipitation, humidity, and UV index levels differ from those of other months.
 TemperaturePrecipitationHumidityUV
January Weather0°C (33°F)60 mm (2.3 inches)86%moderate
February Weather0°C (33°F)85 mm (3.3 inches)86%moderate
March Weather4°C (39°F)69 mm (2.7 inches)85%high
April Weather8°C (46°F)69 mm (2.7 inches)83%very high
May Weather12°C (55°F)47 mm (1.8 inches)77%very high
June Weather17°C (63°F)27 mm (1.1 inches)81%very high
July Weather22°C (72°F)2 mm (0.1 inches)76%very high
August Weather22°C (71°F)10 mm (0.4 inches)60%very high
September Weather16°C (61°F)27 mm (1.1 inches)58%very high
October Weather9°C (48°F)46 mm (1.8 inches)75%moderate
November Weather4°C (39°F)65 mm (2.5 inches)85%moderate
December Weather0°C (33°F)61 mm (2.4 inches)87%low

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