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September Weather in La Grande, United States

Last updated: June 24, 2025

In September, the average temperature in La Grande, United States is a crisp 14°C (57°F). Visitors should be prepared for a temperature range that can dip as low as -2°C (28°F) or soar up to 34°C (94°F). Expect about 35 mm (1.4 in) of precipitation over 5 days, and enjoy a comfortable average humidity of 58%.

September Temperature in La Grande

In September in La Grande, the average temperature is 14°C (57°F). Maximum temperatures can reach 34°C (94°F), while minimums can drop as low as -2°C (28°F). Be prepared for a wide range of temperatures if you plan to travel during this month.

September Weather in La Grande: Daily Temperature Highs, Lows, and Averages

The chart illustrates September temperature patterns in La Grande, showcasing daily minimum, maximum, and average temperatures. It highlights the typical range of temperatures throughout the month, providing insights into weather trends. In La Grande, September typically has an average temperature of 14°C (57°F), with highs reaching up to 34°C (94°F) and lows dropping to around -2°C (28°F).
JanFebMarAprMayJunJulAugSepOctNovDec272735415058686657443529
Data source: Temperature data for La Grande 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 La Grande

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

September Precipitation Trends in La Grande

The chart displays monthly precipitation patterns in La Grande, 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 La Grande, September typically receives around 35 mm (1.4 inches) of precipitation spread over approximately 5 days.
JanFebMarAprMayJunJulAugSepOctNovDec861308986774441635647996
Data source: Precipitation data for September generated using information from the Copernicus Climate Change Service.
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September Humidity in La Grande

In La Grande in September humidity is 58%. With an average temperature of 14°C (57°F), this humidity feels like a refreshing embrace, making it comfortable for traveling as long as you stay hydrated and wear breathable clothing.

September Average Humidity in La Grande

This chart illustrates the average monthly humidity levels in La Grande, 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 La Grande 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 La Grande

In La Grande 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 La Grande.

Maximum UV Index Levels in La Grande for September

The chart shows the monthly maximum UV Index (UVI) for La Grande 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 La Grande typically reaches 8, which falls under the very high exposure category.
JanFebMarAprMayJunJulAugSepOctNovDec357810101098542
Data source: La Grande 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 La Grande Compares to Other Months

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

This table compares monthly weather conditions in La Grande, showing how September’s temperature, precipitation, humidity, and UV index levels differ from those of other months.
 TemperaturePrecipitationHumidityUV
January Weather-3°C (28°F)86 mm (3.4 inches)86%moderate
February Weather-3°C (28°F)130 mm (5.1 inches)86%moderate
March Weather2°C (36°F)89 mm (3.5 inches)85%high
April Weather5°C (42°F)86 mm (3.4 inches)83%very high
May Weather10°C (50°F)77 mm (3.0 inches)77%very high
June Weather14°C (58°F)44 mm (1.7 inches)81%very high
July Weather20°C (68°F)3 mm (0.1 inches)76%very high
August Weather19°C (67°F)16 mm (0.6 inches)60%very high
September Weather14°C (57°F)35 mm (1.4 inches)58%very high
October Weather6°C (44°F)64 mm (2.5 inches)75%moderate
November Weather2°C (35°F)79 mm (3.1 inches)85%moderate
December Weather-2°C (29°F)96 mm (3.8 inches)87%low

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