We had some warm, humid air in the area Monday in advance of a cold front, and when that front arrived, it provided enough energy and instability to touch of some pretty decent storms by Seattle standards.
Several pockets of thunderstorms popped up and rolled through the Puget Sound region overnight, bringing vivid lightning, heavy rain, and a lot of open eyes.
In fact, Sea-Tac Airport broke two daily rainfall records, thanks to the thunderstorms book-ending around midnight. 0.46" of rain fell before midnight, breaking the previous rain record of 0.43" set in 1994.
But the rain kept falling after midnight, and Sea-Tac was up to 0.66" from midnight to 10 a.m. Tuesday, already breaking the daily record for Sept. 4, which was 0.50" set in 1960.
The storm total of 1.12" so far makes up almost our monthly quota of rain, which is 1.66 inches.
Just Another Dreary Day In The Dreary Summer of '07, Right?
The thunderstorms gave me a good excuse, but I was all set to write a story today anyway on how this summer shaped up as Tuesday also marks the traditional end to the summer season, even if the season itself lives on for a couple more weeks.
We've had many people write in lamenting that this has been "the worst summer in history" in Seattle. But believe it or not, this summer hasn't been too far off a normal summer in the Puget Sound region.
Now I'll pause as you slap your forehead and go, "Say, what?!?!?" but the numbers shake it out.
It's seemed like a cold summer, but June's average high was 69.3 degrees this year -- just off the normal of 69.4. July was even hotter than normal, registering a 77.3 degree average, nearly two degrees warmer than the normal of 75.1. August was a little cool, averaging 74.8 degrees, but it's just slightly below the normal of 75.3.
As far as heat waves go, we're also reasonably on par for warm days. Seattle averages 25 days a year at 80 or warmer, 10 days at 85 or warmer, 2 days at 90 or better, and a day at 95 or hotter every other year.
This year so far, with still September to go (and September, on average, is warmer than June), we've had 21 days at 80 or hotter, 7 days of 85+, and just one day where it hit 98 in mid-July, so that counts for one of our 90+ and fulfills our quota of the 95+ for two years.
OK, how about rain? It's been really wet, right?
June had 1.34", just under the normal of 1.51". July was pretty wet -- 1.44", which is pretty far over normal (by summer standards) of the 0.84" average. In fact, it was the 10th wettest July on record. But August was back to just 0.73", again slightly *below* the normal of 1.01".
How about sky cover? It had to be at least cloudy all the time.
June was right on par -- we had 17 cloudy days (defined as a day with 70% cloud cover or more through the day), spot on with the average of 17. July had 10 cloudy days, actually one *under* the normal of 11. We did have two less "clear" days than normal (defined as 30% or less cloud cover), but that's pretty close.
And even August only had 10 cloudy days, which is two under the normal of 12. In fact, add it all up, and between June 1 and August 31st, we've had 37 cloudy days, and normal is 40.
So Why Did This Summer Seem So Gray?
I think I have the answer: We missed summer this year because we were all inside when it happened.
True to Seattle form, just about all the wet and gray weather migrated toward the weekends, while the warm, sunny weather managed to hit in the middle of the week.
Of the 40 days where we had any kind of rain between June 1st and Sept. 4, 17 of those days were on the weekend, with another 7 on Fridays. That accounts for 60% of our rainy days on those three days.
Of the 3.51" of rain we've had between June 1 and Aug. 31, nearly half (1.70") fell on the weekends. In fact, only two weekends during that time period had zero rain from start to finish.
More interesting weekend stats:
Average High Temperatures (June 1 - Aug. 31)
Going back to those stats of 80+ degree days. Of the 13 weeks between June 1 and Aug. 31, it's been over 80 six times on Wednesdays, including the 98 degree day in July. It's been over 80 just twice on Sundays and twice on Saturdays.
How about sunshine? Even more glaring (no pun intended).
I went back and figured a "sunshine index" based on the percent of sunshine received on each day this summer. A 0 means a completely overcast day, while a 10 means a completely sunny day. (A '6' would mean only 40% cloud cover, for example).
I added up each day and divided by number of weeks to get an average "sunshine index" for each day of the week:
So even the fringe weekend days of Monday and Friday weren't the best for those trying to stretch a three day weekend.
Add it all up, and summer was out there this year -- you just had to take off Tuesday and Wednesday to enjoy it.
But! There is hope. For those still itching for a sunny weekend, the long range forecast does show sunshine and comfortable temperatures in the mid-upper 70s. So, summer's not quite over yet -- maybe get in one last little summer vacation this weekend if your past weekends have been, shall we say, not exactly up to sunshine standards.