April 15, 2011

Are Northwest Springs Getting Worse?

I have heard two questions over and over again this week:

Are springs getting worse?
Is this the worst spring on record?

Looking at the data one might argue that the answer to both of these is yes.

For me, it starts feeling spring-like when temperatures get over 55F. In the forties and lower fifties there is a chill in the air, but above 55F there is a different feel, and one doesn't need a sweater to work outdoors. Above 55F I can comfortably run in a tee shirt and shorts.

So let me propose a Spring-Fever Index that counts the numbers of days the temperature is above 55F from February 1 to April 14th. Why April 14th? Because today is April 15th! And April 15th (except this strange year) is tax day.

I think you are learning how science is done!

Now here is a plot of my spring-fever index for Seattle-Tacoma Airport from 1948 though 2011....the entire record at this site (thanks go to Neal Johnson of my department for gathering this data):

SPRING FEVER INDEX at Sea-Tac (click to expand)
The results are shocking, but no surprise to the wet, chilled residents of western Washington.

2011 is clearly the worst year on record with the fewest number of days above 55F!!!

Only two.

You would have to go back to the 1950s to find the runner up.

But it is worse than that.

The biggest decline in the number spring days between two years is between 2010 and 2011! Just like big changes in temperature can crack concrete, a big decline in spring temperatures in consecutive years can crack our spirits! And it has.

Just think of it, last year there were 26 days of ove
r 55F during the period, this year only 2.

A casual glance at this chart suggests the 1950s were somewhat chilly (there was a cold war then of course!) and temperatures warmed up into the early to mid-90s.

In 1992 there were 43 days above 55F! Forget Hawaii that year (1992 had a very strong El Nino)

The last decade has been generally cool except for a few isolated years, like 2010. And these cool years have been reflected in the Cascade snowpack, which has actually been increasing recently.

So it is not your imagination that this was an absolutely abysmal spring...one of the worst ever. Now part of the blame can probably be pinned on the strong La Nina of this winter, but not all, since this year is so extreme.

So the answer to our questions? Yes on both looks pretty good to me.

Eventually, global warming will change the trends upwards, but the coastal Northwest is one of last places on the planet that will experience warming because of our proximity to the slow-to-warm eastern Pacific.

The forecast for this weekend? Just showers, but considerably cooler than normal with temperatures dropping into the 30s on Sunday morning. Don't even think about putting any tomato plants out until June.


  1. Thanks for confirming our suspicions, Cliff. Now as I stand freezing on the soccer sidelines or don hat & gloves before a 35 degree mid-April morning run, I can be assured of the validity of my assertiong that this is indeed the worst spring I've ever experienced. (insert weary grin here)

  2. Great article! Thank you. I agree completeely that 55 degrees is the threshold for feeling spring like. I don't like pulling weeds, etc. when it is below that.

  3. I am going to post that graph on facebook with a link to your blog!!

  4. It is also interesting how slowly the average high temperature creeps up between the end of February and the middle of April. Spring has never been my favorite time of year in the NW. Too many stationary cold lows park themselves over us. Sometimes by the time the weather really improves the summer solstice is almost upon us.

  5. If this is the worst spring can throw at us I'll take it and be grateful I don't live elsewhere.

  6. As a farmer, I also watch for bud break on plants, returning birds from the south, and other indicators. There has been 10 years of cold springs, compared to the 10 before. This is the NPO cold phase is it not? When will it swing back? I had hoped we had bottomed out last year...

  7. As a farmer, I track dates for several events (plant bud break, bird migration, etc)and this is the latest Spring in a trend that has been going on the last 10 years. This would be due to the cool phase of the NPO then? When will it reverse, any clues? I had hoped we had bottomed out last year...

  8. Perception of temperature certainly is relative. I moved here from Missoula, MT in October, so this is my first full winter/spring in Western Washington. To me most of this winter and spring has been the warmest of my life. If the temperature gets over 50 and its sunny I'm out in a tee shirt.

    Now I'm starting to realize why I get dirty looks when I tell a barista on a day like today, "nice weather we're having!"

  9. That graph is disturbing for a couple reasons. First, the constant incline from the 50's to mid 90's. And second, the sudden out of whack since the mid 90's.

    Its like climate change broke its threshold on rare seasonal weather, hot and cold, in the 90's.

  10. As always, love your blog. Thanks for confirming our shared suspicions. Here's hoping we see 55 degrees very soon!

  11. Swallows came through here on Monday. So warmer weather can't be too far behind.

  12. It would be great to see La Nina and El Nino years added to the plot of days above 45 degrees.

  13. I love it! The Spring Fever Index, that is, not this lack of spring weather.

    This, folks, is science at its best: taking our subjective perception of the world and confirming it with an objective measure.

    Or, as Zombie Feynman would put it, "Everything else is just bookkeeping." (http://xkcd.com/397/)

  14. GREAT POST. Specifically for one reason.

    One of my biggest pet peeves, and I'll put myself on the top of the list, is being unaware and have short-term memories about local weather. So we say, this winter has to be the coldest ever, this summer has been the hottest ever, etc. We are all weather narcissists!

    All I'm saying is its refreshing to see data backup what we are truly experiencing. We will continue to complain like always, but be correct for once.

  15. Well, that is validating. I thought I was just getting old and couldn't tolerate mild cold.

    What is interesting to me is that the graph spikes up really high around 1993. But I remember that was a non-summer in Seattle because that was the summer I lived in Sacramento (yay 115 degress that could kill you if you stayed in direct sun too long) and I was constantly hearing complaints back home about how "Seattle never got a summer!" I don't know if on the charts that was the case but I do wonder if the warmer Spring/cooler Summer were related?

  16. This really has been a lousy early spring. But the good news is that the 2009 summer was fantastic, and it looks like it had a lousy early spring too. Also, last summer wasn't so great, and the early spring looked fine. So past performance is no guarantee of future results!

  17. If you add Nina/Nino to another of the same data, can you also add major volcanic eruptions. A straight edge on the graph shows me the mean is increasing until 1996, then a definite decline in the trend, but probably at this point not a huge change in the mean which still looks to be slightly positive for '48-'11.

  18. People's memories are indeed short, and this graph doesn't show a downward trend, but a pretty regular fluctuation. We have some warm springs and some cold springs. Get over it people!

  19. Once we crack 55 degrees, the next milestone is 75. Last year we had trouble with that too.
    I know my spirit is broken for sure. I remember years ago, I'd be wearing shorts to school at this time and feeling good since summer was on it's way. The last few years I still have the furnace on, and wearing a sweatshirt at lest.

  20. 'Global warming hoax?)The projected temperature rise is unrealistic, given that the USA and global temperatures have risen by only 1 deg F (.5 C) in 100 years (or 150 years using the full instrumented data set) during the height of industrial expansion. Even if all this rise is correct, and is attributable to human causes, it is a trivial amount in the natural variation of the Earth, and to suggest the rise would accelerate 5 fold (IPCC best estimate) in this century is incredible. Even after the release of the new data set and procedures by NOAA , which addressed some of the urban heat island issues and dropped the warming 54%. There are also issues of calibration as measurement protocols have changed, issues about the design and placement of the temperature stations, and even the strongly held view by many skeptics that this is a natural rise as the Earth recovers from the Little Ice Age.

  21. Thanks for this post, it was really interesting to see the data behind the weather we've been having!

  22. It could be worse:
    Average Max Temperature JAN-MARCH
    1950 41.58
    1956 44.19
    1957 44.60
    1955 44.68
    1949 44.85
    1951 45.10
    1952 45.66
    1971 45.88
    1985 46.05
    1989 46.27
    1954 46.44
    1980 46.47
    1969 46.59
    1975 46.64
    1960 46.67
    2009 46.73
    2002 46.81
    1976 47.07
    1959 47.13
    1972 47.24
    1982 47.27
    2011 47.53

    #22 all time, not as bad as it could be!

  23. Cliff, based on this post, I finally got off my butt and went to our garden plot at Crossroads. I did most of my weeding and a quarter of the dirt turning (we're not allowed to use roto-tillers) :-(

    I've got my fingers crossed tight that the cold spring just like 2009 MIGHT mean a warm summer like that year... and TOMATOES and PEPPERS and LUFFAS!!

    Don't worry, I won't plant them until Memorial Day weekend, just like we always did at home in New Jersey when I was growing up.

    Thanks as always for the perspective. It's gratifying to have my grumpy old beast attitude about the chilly weather confirmed by statistics. I am ready to turn off the furnace, though.

  24. It would be interesting if you tracked the data to the solar cycles during the same time frame. The last solar cycle and the next solar cycles are estimated to be the longest in over 150 years. How do the longer solar cycles effect our weather in Seattle area.

    Does a relationship exist between spotless days (number days without sunspots) and cool springs? Perhaps a time delay in months or years to see the relationship. It would be interesting to show a chart with spotless days on an annual basis with the data in your chart above.

    From the chart “Top 25 of years with most number of spotless days since 1849” 2007, 2008 and 2009 are in the top 25 for spotless days. 2008 and 2009 are ranked 4th and 5th and 2007 is ranked 20th. A spotless day is the number of days the sun does not have sunspots.

    My observation from reviewing the potential correlation between spotless days and the low number of days above 55 F in the NW.

    Based on reviewing the spotless days chart (see link below) and the number of days greater than 55F over the 1948 to 2011 time frame, the probability of a cool spring 1 to 3 years after a a 160 or more spotless days in a given year appears to be high. Since 1993 the trend shows cooling.

    What is the duration of cooling that you would expect with 3 years of near record spotless days from the sun?

    1954: 9th, est from chart 246 spotless days/1955 days greater than 55 F= 4 (1 year delay)
    1996: 19th, est from chart 170 spotless days/1997 days greater than 55 F= 15 and next 3 years a drop in trend.
    2007: 20th, est from chart 263 spotless days/2008 days greater than 5 F=11
    2008: 4th, est from chart 261 spotless days/2009 days greater than 5 F=11
    2009: 5th, est from chart 165 spotless days/2010 days greater than 55 F=26, 2011 days greater than 55 F= 2 (2 year delay?)

    It would be interesting if you tracked the data to the solar cycles during the sametime frame. The last solar cycle and the next solar cycles are estimated to be the longest in over 150 years. How do the longer solar cycles effect our weather in seattle area.

    Does a relationship exist between spotless days (number days without sunspots) and cool springs? Perhaps a time delay in months or years to see the relationship.It would be interesting to show a chart with spotless days on an annual basis with the data in your chart above. Note that in 1954

    Note chart with Top 25 of years with most number of spotless days since 1849. http://hypsithermal.wordpress.com/2008/09/07/update-to-solaemons-spotless-days-page/


  25. Cliff, Do you plan to do some research on the relationship between spotless days and weather locally?

  26. Kleiber,
    No..the whole thing is pretty far fetched and really doesn't make any sense. Sunspots have returned now and have been back for a while. There is no reason to expect the lack of sunspots three years ago to affect the weather in one part of the country...us. The web page you cited is from some nutty anti-global warming site....cliff

  27. Hi Cliff,

    As a 'just-for-grin' exercise, I plotted the cloud coverage for part of the same period that your Spring Fever chart covers. I only had access to publicly available data, which covered the period from 1973-2000.

    The data for each year measures the daily average cloud cover only for the days between 2/1 - 4/15.

    There seems to be a correlation between a sharp increase in cloud cover and a sharp decrease in the number of 55F days around 1996-97.

    Wonder why the sudden surge in clouds? Is this a long term cyclical event that exceeds La Nina / El Nino cycles in duration?


  28. Did you happen to test your findings for robustness? I'm curious as to how the graph would change if you lowered or raised the cutoff by 10-15 degrees. I ask because making continuous variables discrete sometimes gives weird (for lack of a better term) results.

  29. Cliff, General theory check out NOAA. Low solar activity over years results in cooling on our planet.

    Please note that the current prediction from NOAA for cycle 24 for the next sunspot cycle maximum gives a smoothed sunspot number maximum of about 62 in July of 2013. We are currently over two years into Cycle 24. The predicted size would make this the smallest sunspot cycle in nearly 200 years.

    How does this effect our global temperature is the real question?


    The key here is to not evaluate data in days or months but years and decades.

    Sunspot cycles over the last century. The blue curve shows the cyclic variation in the number of sunspots. Red bars show the cumulative number of sunspot-less days. The minimum of sunspot cycle 23 was the longest in the space age with the largest number of spotless days. Credit: Dibyendu Nandi et al.
    Thoory behind missing sunspots (NOAA)


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

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