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Science Corner

CLIMATE CONTROLS ON THE PACIFIC NORTHWEST

By Kelsey Larson, Water Quality Specialist

Hello qyuuqs News readers,

This article is part one in a series I’ve written about the climate of the Pacific Northwest. This month I cover the phenomena that controls our climate here.

First, when we talk about a particular climate, we are talking about the “average” conditions of an area. For example: A typical winter at Swinomish is rainy and cloudy and the temperature is roughly 40 degrees, give or take 5 degrees.

WHY IS THIS?

The first major factor when it comes to climate is a location’s distance from the equator. The closer to the North or South Pole you are, the more your climate varies from season to season. This is due to the tilt of Earth’s axis—the Northern Hemisphere is tilted towards the sun, which bring longer days and warmer temperatures in June, July, and August. This is at its most extreme at the poles where the summer months bring almost constant sunshine and the winter months bring complete darkness. As we are located 50 degrees north of the equator, we have a good amount of variability between our seasons.

However, the distance north or south of the equator isn’t the only factor. If we travel from La Conner due east 1000 miles we will end up in North Dakota. Though we have not traveled closer to the North Pole, North Dakota experiences an annual snowfall of approximately 38 inches with temperatures that can reach as low as negative 60 degrees. This difference is due to the second major factor regarding a climate—proximity to the ocean. Water retains heat better than land.

1400 miles from North Dakota due east we will end up at the Atlantic coast in Quebec, Canada. Some of you might be thinking, “this is where they experience cold winters AND are located by the ocean!” This is correct! However, the prevailing winds between 30 degrees north to 60 north (and south) of the equator travel from west to east (called “westerlies”) due to the atmosphere’s transport of heat from the tropics to the poles through the Hadley Circulation. Thus, the ocean directly influences the West Coast because we get that moist, warm ocean air immediately, while Canada’s Eastern coast has dry, cold air originating from the continent.

ANNUAL RAINFALL MAP OF WASHINGTON

Our proximity to the ocean is like having a hot water bottle in the winter and a wet rag in the summer!

This is what keeps our temperature changes between seasons smaller than places located farther inland. Something else to consider is if we go an additional

The third major factor affecting our climate—mountains! Think about what happens when you spray a hose at a wall; the water can’t go through the wall so it must either go up or down, or side to side. The Salish Sea is surrounded by mountains with only one way in, which is from the west. This causes a “hose” of air to be channeled into the Salish Sea. As the air can’t penetrate the ground or the mountains it must rise to go over the mountains. As