July 02, 2010

Is June getting cooler?

Here is a fascinating graph from UW meteorologist Mark Albright showing the average temperatures for June at Seattle Tacoma Airport from 1957 to now:

Is June getting warmer? The answer: No. In fact there is a slight cooling trend. Mark notes that June 2010 was 5.5F colder than June 2009!--no surprise to any of us-- and that this June was the 5th coldest in the past 54 years. Again, no big shocker.

Interestingly, regional simulations of the local implications of global warming for western Washington and Oregon suggest an increase of low clouds here as the continent warms--so June may get WORSE under global warming. Why? A greater onshore pressure difference as the interior warm (and pressure thus falls) and stronger offshore high pressure. We just can't win. So you can look forward to Junuary stories in the Seattle Times in 50 years....some things never change. But perhaps we will have an income tax then.

Saturday still looks decent. Showers and clouds on July 4th. And then the big heat wave.


  1. Cliff--

    Can you point us to somewhere on the web where we can learn more about those regional simulations for local implications of global warming?

    I've been naively thinking that "global warming = longer growing season for us" and so maybe my garden tomatoes would actually get ripe for once, and maybe my fig tree might actually ripen its fall crop for once, before the weather turns cold again in the fall.

    But obviously effects like this increased onshore pressure difference make things more complicated than my naive assumptions, and if there's somewhere online that does have simulations about what month-to-month temperatures/rainfall/insolation are likely to be, that would be wicked cool to know about.


  2. Actually,June 2010 was 5.5 degrees cooler, not 7.5, than last year.
    You can look at the climatological data the past 30 years or so and make an even stronger argument that the month of September has become much warmer and drier than a generation ago.I bet when the new 1981-2010 Normals (Climatography of the U.S #84)are released in a few years, the normal average monthly temperature for September will jump significantly over the current average.
    Also, regarding years with a delayed onset of summer-like weather: historically it`s not too unusual to find an extended period of hot weather occurring later in that summer.So all is not lost;it could get quite warm for a long period.( Maybe beginning next week?)My hunch is that this August will be a warm one, especially after four consecutive Augusts will relatively normal temperatures.

  3. We'll see an income tax here when it's 95 degrees in January. Mr. Gates is about to learn a very expensive lesson.

  4. Perhaps the cooling Junuary is due to the North Pacific Oscillation? We are in the cool phase are we not? If we go back more than 53 years, would we see something different?

  5. Even you're doing it, Cliff... informally claiming there's a trend in something, and implying (but being careful not to state explicitly) a tie to a predicted global warming effect when you know there probably isn't a real trend. That graph of Mark's doesn't show anything more than randomness, as any smart reader can see.

  6. Few responses:
    The change is 5.5F..cooler than last year.

    The work on local implications on global warming is found in a few papers in meteorological journals:


    No reason to expect the cooling is associated with the Pacific Decadal Oscillation or any other interseasonal oscillation at this point.

    And finally..I am not claiming a trend...just the opposite...there doesn't appear to be one...and I am trying to understand why.


  7. Cliff,

    I have heard a lot of concerns about what effect tropical storms may have on moving the oil spilled in the Gulf of Mexico. I'm curious as to the flip side of that question.

    Will the oil in the Gulf Coast affect the weather there? Does it change the amount of thermal energy that is stored in the water and therefor accessible to large storm systems to extract?

    Are there other kinds of effects it could or is having on weather? Say for example, if a massive plankton die off is triggered in a climatologically critical area, can that cause measurable changes on the weather?


  8. Coastal cooling under a climate warming scenario has also been looked at in Central California by Bob Bornstein at San Jose State Univ. (my alma mater). He analyzed temperatures at coastal and interior surface stations over the past few decades and determined there's a N-S boundary whereby the areas to the west of this boundary are actually colder due to the enhanced sea breeze circulation. The question is what happens to the position (and strength) of the ITCZ and East Pacific high pressure region in a global warmed future? Many feedbacks at play here which can affect west coast climate.


Please make sure your comments are civil. Name calling and personal attacks are not appropriate.

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