Weather Blog

Summer scoreboard

Summer scoreboard
By YouNews contributor brannman4
Here it is, the last day of summer, and what a summer it's been. Since June 1, we've broken five record high temperatures, and of course, the all-time record high on July 29 when it reached 103. We tied two other daily records.

From my unofficial count, we've had five heat waves, in my loose definition of two days or more above 85 or thereabouts. In a normal year, Seattle averages 25 days at 80 or hotter, 10 of those at 85 or hotter, and 2 of those at 90 or hotter. We average a day at 95 or above every other year.

Well, we blew those out of the water this summer, with as of Sept. 30, 36 days at 80 or better, 21 at 85+, 7 at 90+ and 3 at 95+.

July's average high temperature was 81.0 degrees, the second warmest on record and just a smidge short of the 81.42 set in 1958. We also saw the warmest week on record, with an average high of 93.3 degrees spread out over, actually, eight days from July 26-Aug. 2.

August ended up spot-on normal for high temperatures, and September was trending a bit warmer than normal.

Speaking Of Normal, Where Is It?

Typically a Seattle summer features several nice stretches of mid 70s weather as marine flow locks in for a ritual of morning clouds then afternoon sunshine.

But not this year.

Of the 107 days between June 1 and Sept. 15, just 21 had high temperatures between 73 and 77 degrees (the general normal high temperature during the summer).

And the longest stretch of days with a high temperature in that range was just four days -- June 10-13. There were two other stretches of two days, and every other day with a high in that range was one and done -- either on its way to a much hotter day or coming down toward a much cooler stretch.

Here Comes The Sun.... Again.

Future summers will have a hard time living up to the sunshine of 2009 as well. Between June 1 and Sept. 15, Seattle had just 17 total overcast days, defined as 80% cloud cover through the day or greater. We average, get this, 47 overcast days during the period.

Umbrellas? Who Needs 'Em?

And for rain? Pretty paltry, at least until we got to September.

With 1.40" between June 1 and August 31st, Sea-Tac Airport registered their fifth driest stretch ever during that period.

The transition to autumn is usually quite rapid around here -- to wit, the average high temperature on Sept. 16 is 70 degrees, while 70 degrees is the *record* high temperature on October 16th.

Dry Summer Leads To Dry Winter?

With the climate trending toward a solid El Nino fall and winter, the Northwest is anticipating less rain in the lowlands and less snow in the mountains. El Nino years are marked by splits in the atmospheric flow that shuttles a good portion of storms normally destined for the Northwest to our south into California, leaving our area rather tranquil. But that's not to say we won't have any storms, they'd just be less frequent.