April 20, 2021

The Best April Weather Stretch in Seattle History

If you felt that the weather during the past week in our region has been the best you have ever experienced during mid-spring, with blue skies and perfect temperatures, you are not wrong.

In fact, we broke a new April record at Seattle Tacoma Airport:  the longest run of days reaching 70F or higher during April.  

Yesterday we tied the record, with five days in a row at and above the 70F mark.  Today at 3 PM, we beat the record, with Sea-Tac Airport reaching 70 F.  And we may do it again tomorrow.


The graph of observed Seattle temperatures versus normal highs (purple) and lows (cyan) are shown below, with 70F highlighted with the blue dashed line. We went from cooler than normal before April 12th to the extraordinarily warm period of the past six days, with highs roughly 20F about normal for this time of the year.  July temperatures in April.  And no precipitation for the past week as well.

The regional picture is similar.  For the past week (actually April 12-18th) temperatures have been warmer than normal over the entire state and particularly along the coast (9-15F above normal), where easterly winds kept the cool ocean air at bay.


And the state was drier than normal during the past week, particularly along the western slopes of the Cascades and Olympics, with downslope flow associated with easterly winds and high pressure aloft being primary causes.

If you are a gardener like me you watch the soil temperatures, thinking about putting in those tomatoes or warmer season seeds.   Well, there is good news on that front, with a large increase in soil temperatures (8 inches down) in Seattle (see below)  from roughly 50 to 57F


Temperatures also zoomed up in eastern Washington, as illustrated from the situation at Moses Lake, where soil went from about 51 to 60F.

Tomorrow will be very nice but I have some ill news to tell you.  It won't last.  Clouds and rain are in our future, with a cool, wet weekend ahead.



21 comments:

  1. Do you think that will make for a worse fire season given the higher snowpack? I would assume that all the water and high temps will produce more vegetation that will die later.

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  2. I can't understand the subjective word "best"
    It was sunny and warm but what makes it the best?
    I think using subjective words to describe weather results in people thinking the only good days are sunny and warm
    I lived in Phoenix. We prayed for a cloudy rainy day.
    Every day is a good day for something. Whatever the weather
    Otherwise. I love your blog

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    1. Agreed. Anomalous warm, dry weather pleases us but is not necessarily inherently good. If it becomes a trend it is s disaster. There was a forest fire near our house in western Washington the other day. In April! Not good.

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    2. The majority of human being prefer hot to cold and sunny to wet. Why would anyone ever want to live in a place like Arizona or Florida otherwise? Millions upon millions have decided hot, sunny and even stiflingly humid is where its at.

      If there was not the whole disruption of eco-systems aspect as well as extreme weather, climate change would probably be considered the best thing to ever happen to our species.

      Might be why most people don't care too much if it happens to whatever extreme it ends up being. Many probably are saying bring it on! I don't want to shovel snow anymore or wear heavy clothes. Ever. Endless summer! Whats a few brush fires? Its not MY problem!

      We like what we like, even if its not in our best interest on the long haul.

      Expect more of these hot and dry stretches that have never been recorded thus far, and most everyone to file it under "BEST THING EVER!".

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    3. I would consider the "best" weather as being weather that allows for the greatest range of outdoor activities to be comfortably performed with little to no preparation for the weather conditions. Based on that definition, cold and snowy weather wouldn't qualify nor would rainy weather of any temperature. I suppose we could also disqualify super hot weather from being considered "best" as well but we thankfully don't experience it in these parts.

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    4. I remember being in Los Angeles years ago and hearing a radio announcer say “today’s high will be in the upper 80s, and tomorrow it will be even nicer, with highs in the low 90s.”

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  3. Aw dang, cool rain.. but I guess I can't complain after the best weather streak recorded in april!

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  4. So fellow gardener, should I plant those maters?

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  5. Did anyone see the lights over the Olympics Wednesday morning around 3:30 am? I Have pictures, how can I send them here?

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  6. Since we have had normal rainfall up until this warm up I will concur that this is the best early spring ever, I've have enjoyed it , The birds and wildlife seem to have enjoyed it, first year in a long time my cherry tree blossom haven't been pummeled with rain and wind. I'm resisting bringing the tomato and pepper starts out of the green house for a bit longer knowing that its coming to an end and will stick to the Farmers almanac planting dates for our zone.

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  7. It's even been drier and warmer here in Oregon, leading to some early fire hazard warnings and incessant messaging about apocalyptic doom coming our way unless five feet of rain suddenly appears on our horizon. I guess they've forgotten about the massive wildfires that almost consumed the entire city, not to mention much of the rest of the state last September. If I understand their POV correctly, too much rain leads to too much vegetation - leading to increased wildfire risk and impending doom. But not enough rain leads to widespread fire risks - and impending doom. Either way we're screwed, apparently. Kafka would love this.

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  8. I cant complain about the weather as its been enjoyable but a few observations from out here in N.Bend.
    - Snow has rapidly melted from the mountains
    - Soils seem to have quickly dried out and there was a small grass fire this past weekend along N. Bend way
    - Rattlesnake lake is low for this time of year. Last April you couldnt traverse the entire lake

    Cliff, how do these "insolation blasts" affect the summer water supply as these events surely cause a surge in melting and potentially reduce the advantages we had from an La Nina year? I'm always amazed by how fast the soils dry out in the mountains once the snow has pulled back and precipitation reduces. Hopefully this transition back to cool/wet sticks around until July timeframe to avoid the wildfire event of last year that smoked out the region for several weeks.

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  9. I cant complain about the weather as its been enjoyable but I agree with others that "best" is somewhat a loaded term here. A few observations from out here in N.Bend.
    - Snow has rapidly melted from the mountains these past 2 weeks
    - Soils seem to have quickly dried out and there was a small forest fire this past weekend
    - Rattlesnake lake is low for this time of year. Last April you couldnt traverse the entire lake. I dont know if there is an "official gauge" but it looks closer to July/Aug than April.
    - Pollen count has been insufferable, lived here 10+ years and never had to take allergy medication until now.

    I'm interest to learn how these "insolation blasts" affect the summer water supply as these events surely cause a surge in melting and potentially reduce the advantages we had from an La Nina year? I'm always amazed by how fast the soils dry out in the PNW mountains once the snow has pulled back and precipitation reduces. Hopefully this transition back to cool/wet sticks around until July timeframe to avoid the wildfire event of last year that smoked out the region for several weeks.

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  10. The air has looked so dusty or just polution ridden. Mt Rainier is majorly muted. I wouldn't call it best ever.

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  11. Clouds and rain are good news, not ill. Alas, I'll pray for normal rain thru June and above normal rain in July! It might save from a really bad fire season. If it's stops raining now until September, we are in deep trouble!

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  12. Yes, I have enjoyed it immensely, but I am afraid I must agree that we need some rain to fill the lakes, keep down the fire danger and water our gardens. Hopefully, we'll get back to sunshine before too long.

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  13. Thanks for adding soil temperature. Can you add that info more often in the spring. Also--did you see NYT today--no need for masks outdoors :)

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    1. That’s not actually what the article said. Re-read and you’ll see that there’s a helpful 2/3 rule of thumb.

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  14. How many years out of the last 10 have we set records in april? Remember when it hit about 90 a couple years ago? I guess the jury is still out on climate change though.

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  15. How does the recent stretch of sunny April weather compare, historically, for consecutive rainless days in April??

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  16. The climate is and always has been changing ,technically were still in an Ice age, 17000 years ago was Seattle buried under 3000 feet of ice about when it started to retreat, could it happen again Yes or we could continue to dry out because the climate is not static and is always changing. and yes I believe Humane activity is altering how it changes.

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