Summer 2018: 2nd Hottest On Record In Portland

8pm Labor Day (Monday)

September has arrived and meteorological summer (June-August) has ended.  Sure, there will still be some very warm days and maybe even a 90 or two, but in general we’re done with the hot stuff.

Before summer began I think some of us were hoping it would just be an “average” summer after a series of hot summers.  That sure didn’t happen…it was a scorcher!


  • Weather was consistently warm to hot with few big swings toward extreme heat or cool.
  • But we didn’t break a single daily record high temperature in Portland!  Just one tie (95 on June 20th).  We only hit 100 once (July 15th), which is amazing considering it was the 2nd hottest summer on record.
  • Warm nights:  2 new record warm lows (June 12 & Aug 10) plus 3 tied record warm lows
  • Less morning cloud cover (marine air) than normal.  Seems like late July to mid August we hardly woke up to low clouds.
  • Summer “ended” somewhat abruptly after the 22nd of August.  Of course it didn’t really end but the heat suddenly disappeared.
  • Nelsen Pool Index: My above-ground pool peaked out at 85 degrees in late July and again during the hot spell in early August (same temp as last year).  But it has been very chilly and not really usable since that sudden change the last week of August.  Last year we were able to use it until the fire ashfall finished things off around September 4th.  Again, summer seems to have more abruptly “ended” this year.
  • We were dry, but nothing too unusual.  The very unusual part is the 1.5 month dry spell BEFORE SUMMER EVEN STARTED on June 1st!  That’s what has put us into a drought situation and is extremely stressful to vegetation/bushes/trees.
  • Where was the lightning?  I saw nighttime lightning once in late June  The next morning many of us woke up to a couple loud thunderstorms.  That was it!  What a boring summer, but that saved us from seeing lots more fire starts in the Cascades and possibly Coast Range.  We lucked out in the northern Oregon Cascades this year.

Here are the numbers,

MarkSummer WrapUp

Here’s how other cities around the region rank based on preliminary data:

Seattle:  2nd hottest
Olympia: 8th
Troutdale: 3rd
Salem:  4th
Roseburg: 6th
Medford: 8th
Astoria: 13th
Redmond: 6th
Pendleton: 24th

Note that for a bunch of these cities the top record-holding years are quite recent; we are living through a very warm period!  This has been the 5th consecutive warm/hot summer in the Portland metro area.

MarkSummer RecentYears

I can’t find a similar period within western Oregon in at least the past 100 years.  In the past there have always been cooler summers mixed in with the warm/hot summers, even during the warmer periods like late 1950s through mid 1960s.  Take a look at the past 100 years of Oregon climate zone #2, that includes most of the lowlands north of Eugene.  This is average summer temperature of all the weather stations combined, not including 2018.

download I’m not a climate scientist by any means of course.  But I wonder…

  1. Is the subtropical high that typically moves north in summer in the western USA wanting to build farther north lately, keeping us regularly warmer?  The western USA has warmed far more than east of the Rockies.  Many areas of the Midwest have seen little or no warming the past 100 years during summertime.
  2. If even without AGW (human-caused warming) we would have been in a warm period right now following that cool period around 2008-2011?  Basically is AGW piling extra heat on top of what was already a warm part of the climate cycle?
  3. If we don’t get much warmer the next 10 summers or so due to the Pacific ocean  remaining at almost the same temp.  There should be a limit to how much we can continue to warm with the same cold ocean sitting there giving us summertime marine pushes.
  4. Will we cool the next few years before heating up even more?  Or just stay the same before getting even hotter summers at some point in the future.

As for rain, of course it was dry, as it always is in summer.  But this year we saw less than 1/2 of our typical rainfall

Mark Summer Wrap Rain

It sure wasn’t a record dry June-August, but that follows an extremely dry 2nd half of spring.  The combo of May-August rainfall is the driest on record here.  We need a big soaking soon!

There you go…your Summer 2018 wrap up.  Hope you enjoyed the read and hopefully next year can be a bit more reasonable!

Chief Meteorologist Mark Nelsen


37 Responses to Summer 2018: 2nd Hottest On Record In Portland

  1. Paul D says:

    PDX has hit 91. Another 90+ day for the record books.

    Someone please make it stop!

  2. WEATHERDAN says:

    Now in day 86 of consecutive rainless days in Salem. Beats our old record by 7 days so far. Peace.

  3. Ken in Wood Village says:

    I was just looking at the 12Z EURO and something caught my eye. Close to the end of the run a Low comes down from Canada. The way it comes down is almost like what would happen during winter time. If it was winter, it probably would snow but it’s not. It also so long away that it probably wouldn’t happen but the EURO has shown this I think twice or three times. All I know is next week should start turning cooler and wetter. Maybe we will actually have a fall this year.

  4. Ken in Wood Village says:

    Hmmm, what happened to the Weather Blog on your website?

    • Ken in Wood Village says:

      That’s weird. I’m on my phone and I had the blog on my browser but when I tried to refresh it came up saying website not found. I had to go into the your app then it brought the web page up on my browser. 🤔🙄

      • Ken in Wood Village says:

        Well, I spoke to soon. I’m on my laptop and I can’t get to the blog from

        • Ken in Wood Village says:

          I was able to get to the blog by going to Mark’s Weather Links page. I see they are updating so maybe their IT person forgot to share the link on their page.

    • RJB says:

      Like most web page updates, KPTV’s new update is worse than ever – have to look all over to find anything. No concern for compact efficient web pages anymore. It must have been done by some kid on his I-Pod. And yes they forgot to add Mark’s weather blog anywhere on the site I could find.

      • Ken in Wood Village says:

        Yea, most IT people don’t think about what it should look like when it’s finished. I remember working at this company (which we processed a bank) and the IT person came in during the day (because we work at night) and put new software onto the computers. He left and we started processing the work like normal. Well, when we needed to start printing stuff out, the computer’s wouldn’t send the information to the printers. This was over the Memorial Day weekend, long story short, I worked 18 hours that night/day. Luckily, after 8 hours it was all overtime. It made it worth staying that many hours….lol.

    • Paul D says:

      Looks like they are updating the KPTV web site. My bookmark for the 7-day forecast doesn’t work anymore.

      • Ken in Wood Village says:

        Yea, my bookmark for the weather blog doesn’t work. I had to go to Mark’s Weather Links to get to the blog. You have to love I.T. people (as I roll my eyes) LOL

        • Paul D says:

          I’ve always had a direct link to Mark’s blog, but now the KPTV web site is redesigned, and they’d really dumbed down the 7-day forecast. I guess they fired the person who did color graphics.

  5. Tanis Leach says:

    Pray for a normal or cool summer next year.

    Better yet, pray for a snowy winter (for a 3rd year in a row).

  6. Brandon says:

    00z GFS looks interesting at 240hrs with the low pressure coming pretty close to us. Of course we all know that’ll change but still fun to look at

    • Ken in Wood Village says:

      I saw that too. It’s what we call wish casting…lol. It’s fun to look at but since it’s was out there it’s just wish casting…lol. What I did notice is the 00Z GFS is way wetter than previous runs. Let’s hope it keeps it up. The PNW needs some good rain to put out those fires.

  7. Ken in Wood Village says:

    Wow, the 00Z GFS really got wet. Maybe the EURO will be the same. 🙂

  8. Jason Hougak says:

    The constant back to back to back to back to back… hot summers have got to back off some time ???

  9. Ken in Wood Village says:

    18Z GFS almost looks similar to the 12Z EURO…hmmm!!!

  10. Ken in Wood Village says:

    I’m starting to like the EURO for next week. The 00Z has the PNW under a low for a couple of days. The EURO even gives us a chance of Thunderstorms on Tuesday…hmmm. Things could start getting interesting if this pans out. 🙂

    • W7ENK says:

      I must be missing something, I don’t see thunderstorms on the EURO for next Tuesday. I see stratiform rain moving up from the SW associated with FROPA coming onshore from the W-NW, but nothing stands out to me in the way of convective precip.

      Could you post a link to where you’re seeing this?

  11. Roland Derksen says:

    Thank goodness for that cool off in late August. I’m really enjoying these temperatures in early September, and better yet, I can see the mountains again! Showers are coming here this next weekend- I don’t expect large amounts, but if we get at least half an inch out of it, I’ll be happy.

  12. W7ENK says:

    1957 was warmer, and 1967 looks tied, according to your NOAA Climatology graph. This would make 2018 #3, or possibly #4.

    • Ken in Wood Village says:

      My mom keeps telling me about 1967’s summer. I was born that year. She told me she kept eating ice cubes because it was so hot. She also said when I was born, Portland finally had rain for the first time in weeks. I guess mother nature knew I would love the weather…lol.

  13. My thoughts:

    Summers in The Dalles are definitely getting hotter, but we haven’t set quite the same kind of records the past few years as Western Oregon has. I’ve noticed many more days with only a 5-degree difference between PDX and DLS, as opposed to 10 degrees. For whatever reason, a bigger “share” of the heat is making it west of the Cascade crest.

    If the cool ocean really is going to impose a limit on west side warming, you’d expect the opposite to be true: the Willamette Valley warming more slowly while the Columbia Basin becomes a neverending inferno.

    • Muxpux (Castle Rock) says:

      Not necessarily. The ocean acts as the AC, and the mountains as a barrier. Pendleton had its 24th and Redmond it’s 6th. That’s nothing impressive, yet PDX still managed #2. What’s interesting to me, is surrounding areas weren’t nearly as impressive.

      Really, all this stat proves, is the Urban Heat Island.

      As the city and it’s infrastructure warm, it prevents the air immediately around it from cooling, thus limiting the marine layer. Up here in Kelso, the marine layer was quite present through the summer. There were quite a few days where Portland hit 90, meanwhile Kelso barely managed 80, with a strong marine push around 5pm.

      My guess is Portland’s unique geographic location, as well as the heat island, coupled with overall trends, make these numbers seem more dramatic than they are elsewhere.

      I know quite a few of those PDX 90’s were last second close calls, and occurred after the marine push had taken over Kelso. That tells me there must be some sort of additional heating from atmospheric compression as the marine surge runs into the southerly/easterly flow around PDX.

      • Boring Rain says:

        UHI can be a factor but not to that extent. Here outside the city we still hit 90 over and over just like Portland, with not much infrastructure around.

        • Muxpux (Castle Rock) says:

          Boring is also on the other side of the marine push, protected by PDX.

          What about suburbs like Hillsboro, or a bit north like Scappoose?

  14. Tyler Mode in Battle Ground says:

    41.9 this morning, coldest so far August/September. I love the large diurnal changes that come in September.

  15. Paul D says:

    Lots of stats and all of them bad! Next summer will probably just add to the hot records.

    It’s the new normal for our area 😦

  16. Just going to throw this one out there and should be taken with a grain of salt but have anybody heard anything in regards to the sun itself being to blame for our recent increase in overall temps? It would only take a very slight increase in sun output to raise the temps a few degrees and possibly even change the normal summer patterns in the cooler summer regions on earth. I haven’t heard of any studies in regards to this so curious if others have? Just like Earth, the sun goes through cycles as well.

  17. Paul Bonine says:

    That dry spring followed by consistent heat and almost no precipitation in July and August has put extreme stress on trees around town. Especially trees from summer rainfall areas (E. U.S., Japan). A good example are dogwoods. The often planted eastern Dogwood (Cornus florida) is basically fried if completely unirrigated this summer. Brown, crispy leaves, no fall color coming. Not good for this climate. The western dogwood our native Cornus nuttalii, which actually shuns summer water which creates susceptibility to root pathogens (phytophthora) is perfectly fine, In fact in certain specimens which re-bloom in September anyway the fall bloom this year is spectacular. And they haven’t even wilted. I’ve been watching the weather and plants my whole life and this is about as severe as it gets here. I have a feeling that we are going to see a lot of hot summers in the future. The subtropical SW High used to spend a lot more time up here during the interstadial (warm period ) between ice ages. I wonder if thats what happening now? We’ll have to see. Thanks for the awesome blog Mark. As always.

  18. Gene says:

    Great stats, Mark — very interesting info. Thanks for putting it together for all of us weather buffs. I have a feeling warm/hot summers are going to prevail in the next few years, but we’ll see. I hope we can add some cold/snowy winters to balance out all these hot summers!

  19. Even more astounding than the lack of rain is that we apparently repeated July this summer.

  20. Ken in Wood Village says:


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