Last updated: June 24, 2025
In October, the average temperature in Grand Coulee, United States hovers around 8°C (48°F). You'll experience a range from a chilly minimum of -7°C (20°F) to a pleasant maximum of 26°C (78°F). Prepare for approximately 42 mm (1.7 in) of precipitation spread over 7 days, while the average humidity sits at a comfortable 80%.
In October in Grand Coulee, the average temperature is 8°C (48°F), with maximums reaching 26°C (78°F) and minimums dipping as low as -7°C (20°F). Travelers should be prepared for a wide range of weather conditions during this month.
In Grand Coulee in October, the total precipitation amount is 42 mm (1.7 in) over the course of 7 days.
In Grand Coulee in October, humidity is 80%. With an average temperature of 8°C (48°F), this humidity feels like a damp chill that clings to your skin, making outdoor activities uncomfortable and travel a bit more arduous as the cool air mixes with the moisture, creating a heavy atmosphere.
In Grand Coulee in October, the maximum UV index reaches 5, which corresponds to a moderate Exposure Category. Under these conditions, the estimated time to burn is approximately 30 minutes. For more details, you can check the Hourly UV Index in Grand Coulee.
UV Risk Categories
Weather in Grand Coulee varies notably across the year, with each month offering distinct climate conditions. This page compares October’s weather to other months in Grand Coulee, focusing on differences in temperature, rainfall, humidity, and UV levels.
| Temperature | Precipitation | Humidity | UV | |
|---|---|---|---|---|
| January Weather | -2°C (28°F) | 67 mm (2.6 inches) | 85% | low |
| February Weather | -2°C (28°F) | 47 mm (1.9 inches) | 86% | moderate |
| March Weather | 4°C (39°F) | 46 mm (1.8 inches) | 86% | moderate |
| April Weather | 9°C (48°F) | 39 mm (1.6 inches) | 82% | high |
| May Weather | 15°C (59°F) | 37 mm (1.4 inches) | 77% | very high |
| June Weather | 20°C (68°F) | 13 mm (0.5 inches) | 79% | very high |
| July Weather | 24°C (75°F) | 4 mm (0.1 inches) | 77% | very high |
| August Weather | 23°C (74°F) | 8 mm (0.3 inches) | 62% | very high |
| September Weather | 17°C (62°F) | 24 mm (1.0 inches) | 60% | high |
| October Weather | 8°C (48°F) | 42 mm (1.7 inches) | 80% | moderate |
| November Weather | 3°C (37°F) | 51 mm (2.0 inches) | 87% | moderate |
| December Weather | -2°C (29°F) | 57 mm (2.2 inches) | 86% | low |