Weather Blog

296 days -- and counting -- since we've hit 80 degrees

296 days -- and counting -- since we've hit 80 degrees
Another mostly cloudy summer day in Seattle. (Taken June 27, 2011, courtesy Puget Sound Clean Air Agency Web camera.)

As I was going to open this story with "Does it seem like it's been a long time since it hit 80 degrees?" but judging by the number of frowns this spring and early summer, I don't have to ask the question.

But in case you were wondering just how long it's been, National Weather Service to the rescue.

Lead forecaster and climate guru Dana Felton has discovered that it has been 296 days since the last time Seattle hit 80 degrees -- that would be Sept. 3, 2010 for those too chilly to do the math -- when we hit 84.

The 296-day streak is the fifth-longest in Seattle and we're about to climb into fourth. The record longest is 319 days from Aug. 8, 1959 through June 22, 1960.

Here are the Top 5:

1) 319 days (Aug. 8, 1959 - June 22, 1960)
2) 310 days (Sept. 14, 1979 - July 20, 1980)
2) 310 days (Aug. 1, 1954 - June 7, 1955)
4) 297 days (Sept. 11, 1953 - July 5, 1954)
5) 296 days (Sept. 3, 2010 - present)

Some other stats about the long wait to 80:

The latest date for our first 80 degree day is July 21, set in 1980. Second place is a two-way tie between 1996 and... last year with July 7. There have been three other years -- 1954 (July 6), 1981 (July 3) and 1991 (July 1) -- where we had to wait until July for the first 80 degree day, and 2011 is looking like it'll join that group. As of today, June 27th is in seventh place.

As far as number of days above 80 in a summer, the record fewest is two, set in 1954. There are only four other years -- 1955, 1957, 1980 and 1983 -- when we had fewer than 10 days above 80. Seattle averages about 25 days a year at or above 80.

Last year, we came up just under with 21 days over 80, but 2009 really set a standard with 36 so we're a bit due to sit on the other side of the fence for a while.

When *will* we hit 80 this year?

As of Monday, there is no slam dunk "it's going to be 80+" day in the long range models for the next two weeks, but models indicate there is at least a passing chance we could eke up to 80 degrees just after the holiday weekend.

Official forecasts are in the mid-upper 70s but there have been past signs that 80 is at least not out of the realm. It has also been hotter than normal in the Desert Southwest and I've found that seems to be an early indicator that warmer weather isn't too far off here. But at this point, if we do hit 80, it'll be just barely, akin to how we hit our first 70 for about 3 minutes in early May.

Something to blame for the chilly springs?

Many have noted that this very cool spring has come on the heels of last year's long wait for summer. 2010 saw the record longest wait for the first 75 degree day and the second-longest wait for 80 degrees from Jan. 1. And 2008 was also a very chilly spring.

So, why have our springs been so cold of late?

One theory among many is that we are now entering the cool phase of the Pacific Decadal Oscillation, or "PDO". Recent climate research of the past 15 years or so is indicating that the northern Pacific Ocean also goes through cool and warm phases with respect to water temperatures, somewhat similar to how El Nino and La Nina work in the equatorial Pacific, but on a much longer time scale -- say 30 or so years as opposed to 3-5 years.

For the Pacific Northwest, there has been a noted trend in the climate where we went through a general warm phase from about 1920-1950, then a cold phase from 1950 to the mid 1970s, then a very warm phase through about 2000, varying a bit to a brief cold then warm phase, but trending cold again as we look at the past few years:

The research on this is still ongoing, but the general theory is that a cold PDO translates to overall cooler conditions in the Northwest and vice versa. Now, other climate factors, such as La Nina and El Nino, can play into this, to where perhaps El Ninos are enhanced during warm PDOs and La Ninas are enhanced during cold phases of the PDO. Conversely, an El Nino can be suppressed a bit during a cold PDO.

But don't feel like summers are lost for the next 30 years. The PDO is not the sole force in driving our climate; there are several other factors in play. Instead, I would view this as a bit of weighting the dice that there could be stretches of overall cooler weather in the Northwest for a while, but that's not to say that if this is correct, it will be non-stop cold. Remember, 2009 was one of the hottest summers on record and we were apparently still in the colder phase of the PDO then.

So don't sell the swimming trunks just yet. You just might have to dust them off a little more than usual.