New study provides proof: Sequim is sunny

— image credit:
Sequim Gazette

Sequim lies in a rain shadow, which means we enjoy more days of sunshine than our neighbors in Seattle.


Everybody knows that. Or at least, they do now.


David Britton, a Seattle resident who has a second home in Sequim, is the first to prove with fine instruments and science that what we always knew instinctively is true. We are, comparatively speaking, sunny Sequim.


While most of us, including professional weather watchers, simply eyeball the sky, Britton had a valuable insight: for one year he would measure the amount of solar radiation that both Sequim and Seattle receive.


While he admits solar radiation isn’t directly analogous to the number of sunny days Sequim enjoys, it does provide a way of measuring the difference in the cloud coverage that Sequim sees as opposed to Seattle.


His new methodology provides an “apples to apples” comparison, he said.


After collecting data for a full year, Britton recently concluded that Sequim receives 30 percent more solar radiation each year than Seattle.


“Sequim is quantitatively different,” Britton said.

When it matters most

Perhaps more importantly, Britton’s findings provide data on when Sequim is sunnier than Seattle. “Sequim pulls ahead, dramatically, in the stormier months,” he said.


That means when the weather is worst in Seattle, it is, at least comparatively, much better in Sequim.

Britton pointed out that in March 2011 we had 17 “sunny” days, compared with just four in the Emerald City.


In November and December the rain shadow also “really opens up,” he said.


The more quickly the storms move through, “the more the rain shadow effect,” he said.


Given that as many as 90 percent of the fronts that arrive in Sequim are moving in from the south, that makes sense.


“But there’s also a little bit of black magic,” Britton said. Even when a front arrives from the west, or from another direction, it doesn’t drop as much precipitation in Sequim.


“It’s complex,” Britton said, “and every little hump or bump makes a difference.” Blue Mountain may be creating its own rain shadow, he said.


On one point Britton is emphatic: When a weather pattern stalls, you’re left with “nowhere to run, nowhere to hide.”


That’s when we have those nasty days, sometimes several back to back.

More research needed

Britton was somewhat surprised to find that Port Angeles and Sequim enjoy a similar amount of sunshine during the course of a year. “Port Townsend may as well,” he said.


More work needs to be done, Britton said, noting that since he published the results of his study on his website, it’s been picked up by several news sources. “People are coming out of the woodwork,” to provide him with additional data, he said.


He posits the new interest is due in no small measure to the greater availability, and the reduced cost, of the necessary equipment, including radiation gauges.


He’s always looking for more folks who will join him in his quest.


“I’ll continue to study the shadow,” he said, “but will focus on looking at adjacent locations and looking more at the data from different angles — for example, events. My live station, forecast and data collection will keep going.”

Sunny days ahead

What does all this mean to Sequim?


Britton said sunshine always has been a source of pride to those of us who live here; now we have the proof of our claims.


Sunshine isn’t just an esthetic issue, he pointed out. “There’s a sort of emotional thing, too.” A sunny sunrise, “even if it’s only an hour or two, has a big impact,” he said. “That doesn’t happen much in Seattle.”


Britton also warned against getting carried away with our bragging, noting the claim that Sequim has “300-plus sunny days a year,” is a little misleading. “That may be true, but only if you count sunny days as those with brief moments of sunshine,” he said.


Britton also pointed out that while much is made of the Olympic Rain Shadow, it’s a pipsqueak by comparison with some. “The Great Basin is the great rain shadow,” he noted. From eastern Washington all the way down the Mojave Desert the climate is dry, he noted.


Our advantage lies in our warmer weather.


“Ellensburg is sunny, too, but colder,” he said. On the other hand, “There are no persistent freezing temperatures in the Hoh Valley.” The western mountains don’t just drain the moisture from the eastward-moving fronts, they also stop the maritime air mass which carries with it the warm Pacific air. In the Great Basin the temperatures plunge as the continental air mass moves south from Canada.


Britton, who earned his undergraduate degree at Dartmouth College, and later a Harvard MBA, said he developed his interest in weather while watching the East Coast patterns.


“I became a weather zealot,” he said.


His career took him into software, with a long stint as a director of marketing for Microsoft along the way.

Britton said the best way to stay on top of his research and a good way to learn about the weather in Sequim, is by fanning him on Facebook. See


To learn much more about his ongoing studies, drop by his website at

In the meantime, Britton has two requests: He’s looking for a photo “that really well represents the rain shadow.”


And, he asks, “Does anyone have a good idea for a term for the opposite of the rain shadow? ‘The dark side’? ‘Moss alley?’”


Reach Mark Couhig at mcouhig@sequim



We encourage an open exchange of ideas on this story's topic, but we ask you to follow our guidelines for respecting community standards. Personal attacks, inappropriate language, and off-topic comments may be removed, and comment privileges revoked, per our Terms of Use. Please see our FAQ if you have questions or concerns about using Facebook to comment.

Read the Oct 20
Green Edition

Browse the print edition page by page, including stories and ads.

Browse the archives.

Friends to Follow

View All Updates