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 over 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.