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Pacific Northwest on Track for Warmest Summer on Record

By: Christopher C. Burt, 3:30 AM GMT on August 01, 2015

Pacific Northwest on Track for Warmest Summer on Record

Another heat wave has engulfed much of the U.S. Pacific Northwest the past few days with Seattle, Washington now having observed twelve 90°+ temperatures so far this summer (as of Aug. 1st), an all-time record (9 such days in 1958 was the previous) and also July has been their warmest month ever observed. For some of the cities in the Northwest this has been the warmest June-July period ever measured and, barring a very cool August, will end up being the warmest climatological summer on record (June-August). Here are some details.

After enduring its warmest June on record Seattle has now endured its warmest July on record (see tables below for the figures) and thus its warmest single month on record. It also has been exceptionally dry with only .09” precipitation measured in July (normal is .66”) and .23” in June (normal is 1.43”). However, this is still no match for the June-July period of 1922 when only .03” accumulated! The July 2015 average temperature of 71.2° is also the city’s all-time (any month) heat record (previous 71.1° in August 1967).

Portland, Oregon is also on track for enduring its warmest summer on record following a record warm June and near-record warm July. In fact, July 30th was one of the hottest days on record for much of Oregon’s Willamette Valley. Corvallis Airport reached 108°, tying the town’s all-time (any month) record last set on August 10, 1981 at Corvallis State University (POR since 1889). Roseburg, further south, also reached 108°, just 1° shy of its all-time (any month) record of 109° set on July 20, 1946. Salem and Eugene both observed daily record highs of 105° (all-time records for both cities are 108° set on August 9, 1981) and Portland reached 103°, short of its record of 107° measured on three previous occasions. In Eugene, seven 100°+ days have so far been recorded this summer (including on Aug. 1st), surpassing the previous record of five such back in 1978.

On July 31st The Dalles and Pendleton (in Oregon) hit 109°, the warmest temperatures measured so far during the current heat wave for first order stations. Neither are all-time records (111° on several occasions for The Dalles and 115° for Pendleton). Salem, Oregon has just experienced its warmest month on record (see table below). The coastal sites in northern Oregon and Washington have also been exceptionally mild. Quillayute, Washington was just short of its warmest month on record with a 63.0° average temperature for July (in August 2013 the average was 63.1°). Astoria, Oregon has had its single warmest month since July 1941 with an average of 64.1° (in 1941 the July average was 64.6°).

In the tables below are sites in the Northwest that observed their all-time warmest June on record, how they fared in July, and what their combined June-July averages have been relative to their warmest climatological (June-August) summers on record. It would appear that Medford, Portland, and Salem in Oregon, as well as Seattle, Yakima, and Spokane in Washington are likely to end up with their warmest summers on record barring a very cool August. One aspect of this is that (should the heat trend continue) Yakima, Washington and Portland, Oregon will see back-to-back record warm summers. They just observed their hottest summer on record LAST summer in 2014!

New June monthly heat records (average temperature) for selected cities in the Pacific Northwest (top table), average monthly temperatures for July compared to record values for the same cities (middle table), and June-July average temperatures compared to warmest climatological summer (June-August) on record (bottom table).

Aside from the heat, drought conditions have significantly worsened across the region with 37% of the Pacific Northwest watershed now experiencing extreme drought conditions (a huge weekly jump from just 20% a week earlier).

Pacific Northwest Watershed drought monitor map for July 28th. Note how rapidly conditions have deteriorated in the past several months. Map from NOAA et al.

The hot weather and dry conditions have critically impacted the sockeye salmon runs along the Columbia River and its tributaries. Federal and state fishery biologists estimate that up to 80% of the salmon may perish since the fish become stressed at water temperatures above 68° and stop migrating when the water reaches 74° or higher. Many of the Columbian River tributaries are already measuring temperatures above 76°. The Columbian River itself is running at its lowest level for this time of the year in 60 years according to U.S. Fish and Wildlife Service officials.

The Columbia River is running at its lowest level in almost 60 years for this time of the year, threatening the annual sockeye salmon run. Photo from Freestock. com

P.S. June of 2015 saw many other all-time monthly records at other sites outside of the Pacific Northwest (PNW figures included in the table as well). See:

July saw a continuation of the warmth in the Pacific Northwest, especially in the coastal regions of Oregon and Washington where it was the warmest July on record.

Christopher C. Burt
Weather Historian

Extreme Weather Heat

The views of the author are his/her own and do not necessarily represent the position of The Weather Company or its parent, IBM.

Reader Comments

Thanks Chris.
Great compendium of the wicked weather stats for us here in the PNW. It has been nasty! Today, we'll have RH in the 5 to 15% range by afternoon and the red flag is out for fire. Just hoping to get through to October without any huge conflagrations. The fires we do have going will likely stay alive until the snow puts them out. (writing this from the Kalispell area.)

' Always read and appreciate your blogs!

Thank you, Chris. Although the 85 plus temps in an outdoor, unheated community pool on the Olympic Peninsula is pretty nice, the unusual heat is definitely causing causing problems for migrating fish in the NW.

I believe that the hatcheries have been mostly responsible for keeping the salmon populations going- so really it is the mortality of hatchery fish and any native hatchlings that has a big impact on the population, as well as how many more years this climate continues. There is an article in USA Today, published July 31st, that mentions the hatchery losses. Here is the link and the first few paragraphs.


Heat, drought cook fish alive in Pacific Northwest

Freakishly hot, dry weather in the Pacific Northwest is killing millions of fish in the overheated waters of the region's rivers and streams.

"We've lost about 1.5 million juvenile fish this year due to drought conditions at our hatcheries" Ron Warren of Washington State's Department of Fish and Wildlife said in a statement. "This is unlike anything we've seen for some time."

Sockeye salmon losses in the Columbia River due to the heat are in the hundreds of thousands, said Jeff Fryer, senior fishery scientist with the river's Inter-Tribal Fish Commission. The fish were returning from the ocean to spawn when the "unprecedented" warm water killed them, he said. ...

Edited for clarity, and then brevity.
Killing Heat — It Felt Like 165 Degrees in Iran Today

In Iran it was 115 degrees Fahrenheit today (46 C). Add in humidity and the heat index was a stunning 165 F (74 C). But what they really should be concerned about is the wet bulb reading…

The 10 day forecast for Baghdad -

Sun - 118F / 88F
Mon - 120F / 88F
Tue - 121F / 90F
Wed - 123F / 93F
Thu - 121F / 91F
Fri - 121F / 90F
Sat - `119F / 87F
Sun - 116F / 86F

If I have the count right, Portland OR needs just 3 more 90 degree days to set a new yearly record.
I've hung up all my fly rods for this season. Doesn't make sense to stress the fish even more than they already are stressed out from the low flows and high water temperatures. What a shame.

As we watch the earth heat up and the President issues new rules regarding the use of coal as a source of electric power, the Republican Party, heads forever buried in the sands of denial, vow to fight against anything having to do with conversion from carbon based energy to renewables, yammering about states' rights, of course.

We just seem to be happily waltzing into oblivion. We leave our kids nothing.

Corvallis State University should be Oregon State University, which is located at Corvallis. And yes it has been warm, especially in the Willamette Valley. But the coast is warm too, for the coast. 65 degrees with a 20 mile/hour wind was typical, but temperatures in the 70s with little wind are becoming more common, common enough that people are talking about air conditioners. I used to own one when I lived in the valley, but gave it away knowing I would not need it on the central Oregon coast. After 5 years, I bought one for the bedroom so it would cool down enough to sleep at night.
Here in Montana, it's been one of the coolest summers since the mid to late 1990s. We've barely reached 90º, and then only once or twice. Most days have been in the low to mid 70s with a few days never even reaching 70º. I guess we can be thankful for all the rain and cool weather we've had. I can't remember the last time the grass was green in August and I had to cut the lawn.
SEATTLE - NEW RECORD MOST 85 F DAYS IN A YEAR: 2015 is reportedly already the calendar year that has the record most days with a maximum temperature at the Seattle WA airport of at least 85 F, with 23 such days as of August 11. 1964 and 2014 each had 22 such days.
"After enduring its warmest June on record Seattle has now endured its warmest July on record (see tables below for the figures) and thus its warmest single month on record. It also has been exceptionally dry..."

The word "enjoy" might be truer than "endure" for many Washingtonians.

The salmon. A bad year for fishermen, perhaps. All is not lost for the fish owing to their life cycle that includes spending several years at sea. Problem with the ColumbiA being low is the fish ladders necessitated by damns. Usually navigated well by salmon returning to natal streams, the ladders may not have enough water, warm or cool, to allow the fish to migrate upstream. This could be another reason the salmon are taking side trips.

Dryness is the story to keep an eye on considering Mother Nature's son may carry the usual PacNW fall and winter rain off to California. Continuing or worsening drought would not be good for man nor fish nor fisherman.

Looking forward to your updates.
It's been miserable here in SW Washington. It seems like the seasons were all about 2 months ahead of schedule. Our June weather alone made it almost unbearable, say nothing of July and muggy August. We had flowers blooming in July that usually don't bloom until August. Can't wait for fall weather to arrive -- bring it on. =)
WASHINGTON'S MOST POPULOUS CITY - NEW RECORD MOST CONSECUTIVE 70 F DAYS: The record most consecutive days with a maximum temperature at the Seattle WA airport of at least 70 F, of 62 such days, was set on August 13, 2015. 70 F is about 21 C.

OREGON'S MOST POPULOUS CITY - NEW RECORD MOST 90 F DAYS IN A YEAR: 2015 is already the calendar year that has the record most days with a maximum temperature at the Portland airport of at least 90 F, with 25 such days as of August 18. The record is expected to be extended on August 19. Portland is the most populous city in Oregon. 90 F is about 32 C.

BelmontJeff of Portland, OR has written some excellent, information-packed blog entries about the Pacific Northwest summer.
Heat maps where temperatures observe state lines look so crude. The high temperature records we set in Northwest Indiana in 1988 have not repeated or made a noticeable trend either.
Quoting 19. IndianaJohn:

Heat maps where temperatures observe state lines look so crude. The high temperature records we set in Northwest Indiana in 1988 have not repeated or made a noticeable trend either.

Northwest Indiana is not a part of the Pacific Northwest of the U.S.. The state lines are drawn in for reference purposes and I do see where temperature deviations are strictly observing state lines.
Aren't they using divisional lines?
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