"Why?" you ask. "Because..." I reply, "there's no clouds and no jet trails in it, and we're on the main Pacific flyway between the lower 48 states and Alaska and the Orient. So there's usually hundreds of thousands of cubic feet of jet exhaust polluting the airspace west of town and out over Vancouver Island."
So this really is "special".
On a different note, a rather sour one, here's one of those "freebie" programs that are out there for the taking, but which you should maybe think twice about. It comes with very high praise for doing an excellent job of its primary task. There's only one catch. It also comes with a "LiveUpdate" feature that I'm told is extremely difficult to get rid of, and which will keep trying to re-establish its contacts with its home base even if you shut off Windows Updates. And that's the sort of news which tells me that this "LiveUpdate" feature is probably what we used to call a "Supercookie" or "LSO" (local system object) which never expires, is bigger than a standard cookie, and often (as in this case) contains an executable file (.exe) which can and does "phone home" with your information to its providers, who use that for God only knows what purposes, unbeknown to you. So I'm babbling about it here to give you a "heads up" on this stuff. Not all of these wonderful "freebies" come to you without strings, and you won't see them until they've already done their jobs, and likely not even then, unless you know what to look for. And by then, it could be too late.