2017: 2nd Hottest Summer on Record

7pm Friday

Today has been a wonderful day once again with slightly warmer temperatures; we made it into the lower 80s around the metro area

PDX Observed High Today

Of course August is just about finished with just 6 days to go.  It’s been a hot month across most of the Pacific Northwest, but nowhere else in the USA.  Note that if you take the country as a whole, it’s a relatively cool month.


This is after a slightly warmer than normal July and a warm May + June.  That cool spell from December through April is just a memory now…we’re back into the warm regime that hung over the West Coast for about 2 and a half years.

With only 6 days left to go in Summer, at least meteorological summer and a pretty solid forecast, we can take a look at the stats.  This is likely going to end up as Portland’s 2nd hottest summer on record!  Remember many of us (including me) thought that maybe a summer following a weak La Nina winter might be normal or a little cooler than normal.  That sure didn’t work out.

MarkSummer WrapUp

Are summers getting warmer around here?  Most definitely YES!  Take a look at PDX average temperatures June-August from the late 1930s through this year, a rise of about 3 degrees in that nearly 80 year period.  That’s pretty dramatic.  I even heard a radio talk show host yesterday say that we are cooling, or “some scientists think we are cooling” in the Pacific Northwest.  Where that comes from I don’t know.


Note the last 5 very warm (or hot) summers.  Clearly there is some cyclical climate action going on over the years (warming and cooling), but we are warming and most likely it’s directly related to human-caused global warming.  No, the sky isn’t falling so far in the Pacific Northwest and it’s not the end of society here.  My garden loves this weather and outdoor water activities are thriving.  But you should be aware that we ARE warming and assuming that continues even more people will want/need air conditioning in the future west of the Cascades.  Of course water supply is a much bigger issue, this summer has been even drier than normal, in a place that doesn’t get much rain in summer anyway.   If this is the future we’ll need to store more of that winter rain and snowmelt.  There will be changes in our local vegetation if the warming continues as well.  Look at the difference between Portland and Roseburg as you drive down I-5 as an example.  It’s hotter down there in the summertime and drier too.  Now before you get hung up on the fact that nights are warming faster in urban areas (they are) than rural areas and that skews the graph a bit, note that even the daytime highs have been rising at a similar rate.  Afternoon highs are not affected as much by the heat island effect as overnight lows are.


Since there can’t be too many charts in a weather blog…here you have Astoria’s summer temps since records began at the airport in the early 1950s…warming but at maybe half the rate at a station that is not urbanized and right beside the chilly Pacific.  Interesting eh?


Looking ahead now…the last week of August and first week or so (at least) of September appear to be real scorchers for this time of year.   It’s because upper-level ridging wants to hang over the West Coast in one form or another through the next two weeks as it has most of this month.  The ECMWF model’s ensemble forecast of 850mb temperatures.  That’s the temperature at 5,000′ over Portland in celsius:


The green line is the average for this time of year…wow, the entire period is well above average.  You can see two obvious peaks both in the ensembles and most of the operational run as well.  The first is this coming Sunday/Monday, then again right over Labor Day Weekend.  These will be the hot periods, with more reasonable, but still warmer than normal temps the 2nd half of next week.  This is very bad for our native shrubs/trees which will have gone over 2 months with no substantial rain.  They may end up going 3 full months without a soaking.  Even in our dry summer climate that’s a bit extreme.  Only 15 of all 51 ECMWF ensembles produce 0.10″ of rain or more into the 2nd week of September.


The GFS model and GEM are similar showing the ridging over the next 2+ weeks like the ECMWF monthly run from last night:



So keep watering all your shrubs and maybe even some trees too.  Summer 2017 is definitely not finished yet.

Chief Meteorologist Mark Nelsen

33 Responses to 2017: 2nd Hottest Summer on Record

  1. …craziest thing is going on right now here in Cove…there’s a bit of a sprinkle storm going on….wind came out of nowhere to 33, and the temp has gone up to 88, from 75 an hour earlier at 10pm…

  2. Jake-(Gresham near Nadaka Nature Park) says:

    All this take on global warming and hotter Summer weather not necessarily being caused by humans is rather upsetting. It’s a factor hands down. Not to the extent the cycle of the sun has on us or what the jet stream does, but it’s there. It is another factor. I frequent this blog and have seen this before. My tid bit without trying to sound hottie tottie (I graduate with a degree in science) is as such.

    Remember the Ozone hole and PSCs of those banned aureoles? I was a kid when that was an “issue.” That problem won’t go away till 2050. To say the air can’t be polluted is arrogant. Open your windows to get fresh air? Ever try to jog down a path next to the freeway during rush hour? Air gets dirty.

    Smog can blot out the sun. Cause asthma that shortens people’s life span by several years (see cases in heavily dense and polluted cities). That alone should bring thought to people about this.

    There are photos of people during expeditions in black and white in front of glaciers. That now? Are entirely gone. Millions of tons of ice. About 3 / 4 generations. One must considered that no sun cycle, jet stream cycle or any other weather pattern has ever done this before.

    We are looking at weather that is never before seen on earth because we’re causing a factor that is new. People be-raid the scientists on the data. But the weather logs only go so far back. The simulations? Even less. But the output is warning us.

    Currently all animal life on earth is 50% less then what it was one generation ago. Glaciers are again. Disappearing. Deserts are expanding at an accelerated pace. Oceans are warming.

    In summary, climate change (it’s proper name). Doesn’t mean warmer days throughout the year. It overall means more violent weather. All the time. In the form of droughts that last decades, hurricanes in new categories, tornado storm events that require State evacuations and blizzards that will easily surge out of the rich atmosphere right after a few hot weeks in Spring. The worst will be the rising ocean levels. The State of Florida and what has already been put in place to hold back the tide has cost millions.

    • JohnD says:

      Thank you Jake. Your analysis is passionate, heartfelt, profound and staggering.

    • Alohabb says:

      Reading about the rising seas and seeing what will happen to Hawaii in the next 40-50 years is scary. If they don’t do something soon all that land will be gone. Even the famed Waikiki beach looks in bad shape today compared to the last decade.

  3. Joshua Downtown PDX says:

    Mark, talk me off of the ledge and tell me that we won’t hit 100 or very close to it Sunday – Wednesday. It looks possible to my untrained eye. This late summer heat is getting downright silly.

    • Paul D says:

      Truly disgusting. I’m so glad for once I’m out of town during one of our nasty heat waves. I briefly saw 74 today before it started cooling down – soooo nice!

    • JohnD says:

      Yep. Have totally agree. Enough is enough. But who can “argue” with “Mother Nature”?’

  4. W7ENK says:

    Second hottest? I’m not so sure about that…

    According to your graph, looks like 1967, 2004 and 2014 were on par with this Summer, any one of those could have possibly been marginally warmer, but 2009 most definitely shows as warmer, and of course the blazing hot 2015. So “third hottest” would be appropriate, but the possibility exists that this Summer falls to 4th or 5th, maybe even 6th place… I’d have to see the actual raw numbers.

  5. Joshua Downtown PDX says:

    70.1 degrees outside right now. Talk about an urban heat island… I notice that the high temps here are usually 2-3 degrees cooler than PDX, and the lows are 2-5 degrees warmer.

  6. Boydo3 N. Albany says:

    The warming is really evident in Alaska.

  7. boninepaul says:

    Warmer summers in the past 20 years have already changed the plant palette for our region (the kind of plants we can grow). I wrote a book for Timber Press out in December ‘Gardening in the Pacific Northwest: The complete Homeowners Guide’. I organized the PNW by climate region and assigned plants that grow in each zone. I factored in our warmer summers which expands what we can grow. In the past 20 years species such as Crape Myrtle (Lagerstroemia)- which was always hardy here but shy to bloom. These shrubs/trees are booming in popularity because of the recent warmer than average summers. In fact, warmer summers will affect gardening significantly from the expanded amount of Tomatoes that we can grow to success with such hardy subtropical plants like Caesalpinia gilliesii (Bird of Paradise Shrub). Cold hardiness is even affected by warmer summers. Higher summer temperatures actually cause woody plants to be hardier to cold in winter. The “wood” hardens with an accumulation of heating calories and thus can survive colder temperatures in winter. ( An example of this is Loropetalum chinense ‘Rubrum’- Fringeflower). An evergreen shrub from SW China that thrives in hot summers- which prepare it for colder temperatures in winter. In fact, this an many other shrubs and trees are recommended for Portland but not for Seattle. Even though winters are slightly milder in Puget Sound they still do not get enough heat for many things to thrive- which do in Portland. Its amazing to me that we are almost continually breaching our average of 90ºF degree days each year and because of this look for big changes in the plants sold and grown here. And check out my book for detailed descriptions of climate and plants.

  8. Roland Derksen says:

    I won’t argue that summers are getting warmer and sunnier, but that doesn’t translate into being “boring” for me. If i’m going to get bored it will be in the late fall through early spring months when we usually get one low pressure system after another. It won’t take long to remember the feeling.

    • lurkyloo says:

      Yeah, and Corpus Christie, Rockport (ouch), San Antonio, etc. They all have a big old problem named Harvey.

      Hope our friend JJ is doing okay. He’s always so proud of his new climate, but probably not today!

    • pappoose in scappoose says:

      Lotsa folks gonna float away.

    • JJ78259 says:


      We only got about 2 inches in San Antonio this weekend. Just enough to wash in the lawn fertilizer I put on thursday. It is beautiful today with north breeze 84 and a little cool out. This week will be spectacular in San Antonio! My pump sales to rental companies have gone thru the roof! We can’t build enough to satisfy the need this year! Now with the Hurricane we are adding another shift! Take care I may have to come up to Portland to get some HOT weather we are a little cool this week!

    • lurkyloo says:

      Glad you didn’t get hammered, JJ. Been watching a lot of coverage of the storm and praying for all the folks that got hit hard in Texas. The slogan is “Don’t mess with Texas”, but damn, Harvey sure did (and still is).

  9. Our summers are definitely comfortable (no humidity, no insects, no bad weather) but man, they’re boring. What I would give if we could have some decent thunderstorms once a week and some major storms (l mean Front Range-style T-storms) just once a summer. I’ve noticed that every August/September, I’m itchy for some rain to finally fall (and the opposite in March/April).

    Josh, you’re right that people exaggerate how long our winters last. It’s really only bad for like four months (in most years) and the other rainy months are the same as or drier than much of the country. More people than I can count have compared our climate to the UK, when we really don’t much in common with their climate. We really have a mild Mediterranean climate, while the UK has an oceanic climate with consistent rain and cloudiness throughout the year, and much cooler temps than us.

    • JohnD says:

      The term is “Marine” here. Four seasonal changes. Generally moderate; but not without occasional extremes. “Mediterranean is in areas like Sacramento–and, of course, the Mediterranean!

  10. Boring 550' says:

    Yes, our summers have been getting warmer over the past 100 years. In fact, every month of the year (except December I believe), is getting increasingly warmer here in Portland. But Mark, I believe you made a grave error by saying it’s likely man made warming. Ugh. I will completely agree with the idea of global warming up until you say it’s man made. You can easily show me facts and evidence of it getting warmer. But showing it’s man made? I see no evidence of that. You showed a few graphs of temperatures gradually increasing over 80 years from 2 locations in NW Oregon. Where does it show that it’s man made Mark? I suggest you don’t make a little jab like that without trying to explain yourself. And I know, this kind of comment is exactly what you don’t want to see because you don’t want to get all political, so maybe don’t try to get away with it. 😉

    • Dave Brown says:

      Bingo! That’s telling it like it is. Good job!

    • muxpux (Longview) says:

      He’s referring to the heat island effect keeping low temperatures warmer, thus raising the average temp.

      It’s pretty proven that metro areas contain lots of concrete and asphalt that absorbs heat during the day and radiates it at night. Often in the summer Portland won’t get below 60, and away from town it’ll be in the low 50’s or 40’s even.

      I think that’s the point

    • Boring 550' says:

      He also referenced how Astoria is heating and noted how it isn’t urbanized. So he is not just noting the urban heat island.

  11. Paul D says:

    That’s a record we can do without.

    Hopefully October ushers in the normal cooling it’s famous for.

  12. JERAT416 says:

    Sometimes our winters are warm in the NW and everyone else is cold. So I guess this is how we balance it out. I’m not convinced of ACC to begin with but that’s another debate. That being said, if that’s the cause of warmer summers, why isn’t it the case across the country? The whole concept requires us to find steadily rising temperatures across the globe. Some places would be more or less obvious. September is my favorite time of year. Cool, crisp mornings and even if it hits 90, it cools quickly.

    • Joshua Downtown PDX says:

      It’s amusing to me that almost everybody thinks our summers are nice in Portland. In reality, they are hot, dry, dusty, brown, weather-less, and smoky. Not only are our summers getting warmer, but they are getting longer. People that say it rains 9 months out of the year here are ignorant. April – October are not “wet”. That’s 7 out of 12 months. We have such amazing natural beauty here, and I very much hope that our seemingly new climate is able to maintain that.

    • Gene says:

      I would make the argument that our summers ARE nice; in fact, compared to much of the rest of the Continental United States, we have stunningly amazing summers. Would you rather be in Arizona right now? How about Texas and parts of the Gulf Coast today or in the upcoming week? Most summers, would you rather be in the stifling heat and drenching humidity of the Midwest, Southeast or East Coast, or experiencing the warm, sunny and temperate conditions of most Northwest summers?

      In the path of last week’s eclipse, which part of the U.S. had the best viewing conditions, weather-wise? Most likely it was Oregon. Our eclipse viewing conditions were just about perfect, in fact.

      I have lived here my whole life, and I think it’s a safe bet to say that the vast majority of Oregonians appreciate our typically wonderful summer weather, and would consider them to be a great reprieve/contrast to our long, dark, rainy winters (which I enjoy, too — especially when snow and cold are mixed in). Enjoy the seasons — this is summer, and fall will come soon enough.

    • Love summertime here in the great ‘ole PNW. Wouldn’t live anywhere else.

      • JERAT416 says:

        I’ve always lived here also but I’ve vacationed in humid and hotter places. I also enjoy thunderstorms, but if we had them, you would find people would complain about that too. Whether it be kids playing coming inside due to close proximity lightning, dry lightning starting fires, or camping gear left out possibly getting wet. We all have our preferences. It’s true that we don’t have 9 months of constant rain. However, seemingly endless weeks of dreary, dripping skies are always worth it when summer comes.

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