October weather forecast
Grand Coulee, WA

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Weather in October

October, the same as September, in Grand Coulee, Washington, is another mild autumn month, with an average temperature fluctuating between 41.4°F (5.2°C) and 56.3°F (13.5°C).

Temperature

October is marked by a significant decrease, with the average high-temperature retreating from an agreeable 72.7°F (22.6°C) in September to a mild 56.3°F (13.5°C). Throughout the month of October, the nighttime temperature dips to an average of 41.4°F (5.2°C).

Humidity

In October, the average relative humidity is 63%.

Rainfall

In Grand Coulee, Washington, in October, it is raining for 10.3 days, with typically 0.87" (22mm) of accumulated precipitation. In Grand Coulee, Washington, during the entire year, the rain falls for 102.1 days and collects up to 9.65" (245mm) of precipitation.

Snowfall

Months with snowfall in Grand Coulee are January through April, September through December. In Grand Coulee, during October, snow falls for 0.2 days and regularly aggregates up to 0.04" (1mm) of snow. In Grand Coulee, Washington, during the entire year, snow falls for 33.4 days and aggregates up to 14.65" (372mm) of snow.

Daylight

The average length of the day in October is 10h and 49min.
On the first day of the month, sunrise is at 6:56 am and sunset at 6:34 pm. On the last day of October, sunrise is at 7:40 am and sunset at 5:38 pm PDT.

Sunshine

The average sunshine in October is 6.7h.

UV index

The average daily maximum UV index in October is 2. A UV Index reading of 2, and below, represents a low threat to health from exposure to the Sun's UV radiation for ordinary individuals.
Note: In October, the maximum UV index of 2 translates into these guidelines:
Children, babies, and those with sensitive skin should always be shielded from long periods of sun exposure. To avoid the Sun's strongest rays, limit exposure around the mid-day period. Sunglasses that ward off UVA and UVB rays play a pivotal role in reducing solar eye damage. Be careful! The Sun's UV radiation can nearly be doubled by the reflective quality of snow.
Updated: Jul 28, 2024
Published by: Weather U.S. | About Us
Data Sources | Weather Forecasting & Climate

Frequently asked questions

What is the temperature in October?

An average high-temperature, in October, in Grand Coulee, is 56.3°F (13.5°C) and the average low-temperature is 41.4°F (5.2°C).

What is the average humidity in October?

The average relative humidity in October is 63%.

How much does it rain in October?

In Grand Coulee, in October, during 10.3 rainfall days, 0.87" (22mm) of precipitation is typically accumulated.

How many days does it snow in October?

In Grand Coulee, in October, during 0.2 snowfall days, 0.04" (1mm) of snow is typically accumulated.

What is the average length of the day in October?

In October, the average day length is 10h and 49min.

When are sunrise and sunset in October?

On the first day of October, sunrise is at 6:56 am and sunset at 6:34 pm. On the last day of the month, sunrise is at 7:40 am and sunset at 5:38 pm PDT.

How many hours of sunshine does Grand Coulee have in October?

In Grand Coulee, the average sunshine duration in October is 6.7h.

How high is the UV index in October?

The average daily maximum UV index in October is 2. A UV Index of 2, and less, symbolizes a low health threat from exposure to the Sun's UV radiation.
Average humidity
Average rainfall days
Average snowfall days
Average daylight
Average sunshine
Average sunshine days
Average UV index
Average cloud cover
Average visibility

Average temperature in October
Grand Coulee, WA

Average temperature in October - Grand Coulee, WA
  • Average high temperature in October: 56.3°F

The warmest month (with the highest average high temperature) is July (84.9°F).
The month with the lowest average high temperature is December (31.6°F).

  • Average low temperature in October: 41.4°F

The month with the highest average low temperature is August (61.3°F).
The coldest month (with the lowest average low temperature) is December (21.4°F).

Average pressure in October
Grand Coulee, WA

Average pressure in October - Grand Coulee, WA
  • Average pressure in October: 30.03"Hg

The month with the highest atmospheric pressure is January (30.18"Hg).
The month with the lowest atmospheric pressure is August (29.91"Hg).

Average wind speed in October
Grand Coulee, WA

Average wind speed in October - Grand Coulee, WA
  • Average wind speed in October: 5.9mph

The windiest month (with the highest average wind speed) is April (7mph).
The calmest month (with the lowest average wind speed) is January (4.9mph).

Average humidity in October
Grand Coulee, WA

Average humidity in October - Grand Coulee, WA
  • Average humidity in October: 63%

The month with the highest relative humidity is January (89%).
The month with the lowest relative humidity is August (36%).

Average rainfall in October
Grand Coulee, WA

Average rainfall in October - Grand Coulee, WA
  • Average rainfall in October: 0.87"

The wettest months (with the highest rainfall) are May and December (1.18").
The driest months (with the least rainfall) are July and August (0.2").

Average rainfall days in October
Grand Coulee, WA

Average rainfall days in October - Grand Coulee, WA
  • Average rainfall days in October: 10.3 days

The month with the highest number of rainy days is March (12.1 days).
The month with the least rainy days is August (3.2 days).

Average snowfall in October
Grand Coulee, WA

Average snowfall in October - Grand Coulee, WA
  • Average snowfall in October: 0.04"

The month with the highest snowfall is January (4.41").
The months with the least snowfall are May, June, July and August (0").

Average snowfall days in October
Grand Coulee, WA

Average snowfall days in October - Grand Coulee, WA
  • Average snowfall days in October: 0.2 days

The month with the highest number of snowfall days is December (10.5 days).
The months with the least snowfall days are May, June, July and August (0 days).

Average daylight in October /
Average sunshine in October
Grand Coulee, WA

Average daylight in October / Average sunshine in October - Grand Coulee, WA
  • Average daylight in October: 10h and 5min

The month with the longest days is June (Average daylight: 16h and 0min).
The month with the shortest days is December (Average daylight: 8h and 30min).

  • Average sunshine in October: 6h and 4min

The month with the most sunshine is August (Average sunshine: 12h and 6min).
The month with the least sunshine is January (Average sunshine: 4h and 6min).

Average sunshine days in October
Grand Coulee, WA

Average sunshine days in October - Grand Coulee, WA
  • Average sunshine days in October: 19.2 days

The month with the most sunshine days is August (25.8 days).
The month with the least sunshine days is March (14.7 days).

Average UV index in October
Grand Coulee, WA

Average UV index in October - Grand Coulee, WA
  • Average UV index in October: 2

The month with the highest UV index is July (UV index 7).
The month with the lowest UV index is November (UV index 1).

Average cloud cover in October
Grand Coulee, WA

Average cloud cover in October - Grand Coulee, WA
  • Average cloud cover in October: 31

The month with the most cloud cover is January (Cloud cover 55).
The months with the least cloud cover are July and August (Cloud cover 12).

Average visibility in October
Grand Coulee, WA

Average visibility in October - Grand Coulee, WA
  • Average visibility in October: 6mi

The months with the highest visibility are March, April, May, June, July, August, September, October and November (6mi).
The months with the lowest visibility are January and December (4mi).

Grand Coulee, Washington, USA

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