Monthly weather forecast and climate
Grand Coulee, WA

The average high-temperature, is 33.1°F (0.6°C), while the average low-temperature is 23°F (-5°C). In Grand Coulee, 1.1" (26.9mm) of precipitation is typically accumulated.
Weather in January »
In February, the average high-temperature is 39.9°F (4.4°C), and the average low-temperature is 25°F (-3.9°C). Throughout February, 1" (25.4mm) of precipitation is accumulated.
Weather in February »
In Grand Coulee, in March, the average high-temperature is 52°F (11.1°C), and the average low-temperature is 30.9°F (-0.6°C). Throughout March, in Grand Coulee, Washington, 0.9" (23.1mm) of precipitation is accumulated.
Weather in March »
The average high-temperature, in April, is 61°F (16.1°C), while the average low-temperature is 37°F (2.8°C). In Grand Coulee, 0.9" (22.1mm) of precipitation is typically accumulated.
Weather in April »
The average high-temperature, in May, is 70°F (21.1°C), while the average low-temperature is 45°F (7.2°C). In Grand Coulee, in May, 1.1" (29.2mm) of precipitation is typically accumulated.
Weather in May »
In Grand Coulee, in June, the average high-temperature is 78.1°F (25.6°C), and the average low-temperature is 51.1°F (10.6°C). During June, Grand Coulee regularly aggregates up to 1.1" (26.7mm) of precipitation.
Weather in June »
July and August, with an average high-temperature of 87.1°F (30.6°C), are warmest months. In Grand Coulee, 0.6" (16.3mm) of precipitation is typically accumulated.
Weather in July »
July and August, with an average high-temperature of 87.1°F (30.6°C), are warmest months. The month with the least rainfall in Grand Coulee is August when 0.3" (7.1mm) of precipitation is typically aggregated.
Weather in August »
In September, the average high-temperature is 77°F (25°C), and the average low-temperature is 48.9°F (9.4°C). During September, Grand Coulee regularly aggregates up to 0.4" (11.2mm) of precipitation.
Weather in September »
In Grand Coulee, the average high-temperature is 61°F (16.1°C), and the average low-temperature is 39°F (3.9°C). Throughout October, 0.7" (17.3mm) of precipitation is accumulated.
Weather in October »
The average high-temperature, is 43°F (6.1°C), while the average low-temperature is 30°F (-1.1°C). In Grand Coulee, in November, 1.3" (33mm) of precipitation is typically accumulated.
Weather in November »
December is the coldest month, with an average high-temperature of 32°F (0°C) and an average low-temperature of 21.9°F (-5.6°C). December is the month with the most rainfall, with 1.4" (36.8mm) of accumulated precipitation.
Weather in December »

How much does it rain in Grand Coulee?

During the entire year, Grand Coulee aggregates up to 10.8" (275.1mm) of precipitation.

When are the longest days in Grand Coulee?

The month with the longest days in Grand Coulee, Washington, is June, with an average of 16h of daylight.

What are the warmest months in Grand Coulee?

Warmest months in Grand Coulee, Washington, are July and August, with an average high-temperature of 87.1°F (30.6°C).

What is the driest month in Grand Coulee?

The month with the least rainfall in Grand Coulee is August when 0.3" (7.1mm) of precipitation is typically aggregated.

What is the coldest month in Grand Coulee?

The coldest month in Grand Coulee is December, with an average high-temperature of 32°F (0°C) and an average low-temperature of 21.9°F (-5.6°C).

What is the rainiest month in Grand Coulee?

December is the month with the most rainfall in Grand Coulee, with 1.4" (36.8mm) of accumulated precipitation.

What is the month with the shortest days in Grand Coulee?

With an average of 8.5h of daylight, December has the shortest days of the year in Grand Coulee, Washington.
Average rainfall - Grand Coulee, WA
Average daylight - Grand Coulee, WA
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