Weather Blog

First half of year wraps up among coolest on record

First half of year wraps up among coolest on record
Downtown Seattle (trust us, it's there behind the clouds) as seen from the Puget Sound Clean Air Agency visibility camera early Sunday morning, May 15, 2011.

2011 is halfway through and if we to give a mid-season weather report card, it'd get an 'A' in rainy days and a 'D-' in sunshine.

Going by average high temperature, the period from January 1 through June 30th was 54.2 degrees this year. That puts it tied for sixth coldest on record at Sea-Tac Airport.

1) 51.9 - 1950
2) 52.1 - 1955
3) 53.3 - 1971
4) 53.6 - 1954
5) 54.1 - 1956
6) 54.2 - 2011
6) 54.2 - 1953

It's interesting to note that five of those seven years listed are in the early 1950s. 1950 itself was skewed a bit by the massively cold January (with its *average* high temperature for the entire month of just 30.4 degrees) but this does illustrate the whole cold phase of the Pacific Decadal Oscillation that was apparent in the early 1950s. (See my earlier blog entry on what the heck the "PDO" is all about.)

But in an interesting twist, only two of those years -- 1954 (2nd) and 1950 (10th) were in the top 10 for coldest second half of the years.

How about rainfall? By amount, it wasn't too extreme. Seattle has 23.42" in the rain bucket so far --- well above the annual pace of 37 inches and 9th most through the first half of the year. (Most was 28.71" in 1971, 1950 was second (surprise!) at 27.34".

However, the number of days it rained is what I think what most people will remember. We've had measurable rain on 106 days this year -- or 59% of all days of the year so far. That is tied with 1950 for second-most behind... 2010, which set the record last year at 111 days. Seattle averages about 152 days a year so we're either going to blow past that, or have a very dry second half. The record most-frequently-wet year was -- you guessed it -- 1950 at 194, but last year was close at 190.

And as you might expect, all those rainy days have taken a toll on our sunshine. So far, we've only had 13 official sunny days -- defined as 30 percent cloud cover or less during a day. But the real statistic is that the winter has been brighter than the spring. Of those 13 days, three came in January and five came in February. Meaning February had just as many sunny days as our entire spring and then some (March 1-June 30).

But we do always joke that summer doesn't really begin in Seattle until July 5th and sure enough, the weather does appear to be getting sunnier and warmer right on cue.

300 days now since 80 degrees

By the way, for those keeping track, Friday marks 300 days since we last saw 80 degrees. That's fourth-longest stretch behind 319 in 1959-1960. July 1 also ties for sixth-longest wait to our first 80 degree day.