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jhodlof wrote:I forecast snow and an open snowbowl by Thanksgiving weekend.

rlrjamy wrote:Yeah..Today is the 1st day of autumn.

jhodlof wrote:Perhaps my "clock work" reference was vague.

There is a widespread misconception in this country--which extends, I might note, to the makers of most calendars, dictionaries, and encyclopedias--that summer "officially" starts on the day of the summer solstice, June 21 or 22, which is the longest day of the year. Americans also believe (1) that there is some valid scientific reason for doing it that way, and (2) that everybody in the Northern Hemisphere does it that way, and always has.

None of these things is true. So far as I have been able to discover, no scientific or governmental body has ever formally declared that summer starts on the solstice.

Certainly there is no good scientific reason for doing so. In the Northern Hemisphere the period of maximum daylight falls roughly between May 7 and August 7--in other words, the six weeks before and after the solstice. The period of maximum temperature, on the other hand, is June 4 through September 3. (The period of max temperature in the mid-latitudes always lags about 25 to 30 days behind the period of max daylight, due to the fact that the earth heats up and cools off relatively slowly.)

"It isn't really clear how the astronomical definition [i.e., summer starts on the solstice] got started," says Kevin Trenberth, a climate researcher at the University of Illinois in Urbana. "Although the sun-earth geometry is clearly the origin of the seasons on earth, it has nothing directly to do with temperature or weather."

He notes that meteorologists define summer simply as June, July, and August. "For practical purposes, the meteorological definition is the best one, being very closely to the [weather] statistics," he says.

In fact, it appears that June 1 was accepted as the beginning of summer in the United States until relatively recently. According to many older reference books, ranging from The American Cyclopedia (1883) to Webster's Third New International Dictionary (1966), summer in the U.S. comprises the months of June, July, and August. Seasons in Britain, for no particularly good reason, start a month earlier.

The Oxford English Dictionary, somewhat confusingly, says that spring in Britain (and evidently in Ireland) runs from February 1 through April 30, but that summer runs from mid-May to mid-August. This leaves the first two weeks in May mysteriously unaccounted for, by my reckoning, but that is England for you.

The Irish appear to have opted for May 1 as the starting date of their summer, but it was not always thus. I have here an old Irish guidebook (1938) that says summer begins the day after the third Saturday in April (Sunday, presumably) and ends the day after the first Saturday in October. The May 1 starting date may strike Americans as odd, but it sure beats what they were using in 1938.

Summary
•El Niño is present across the equatorial Pacific Ocean.
•Sea surface temperatures (SST) were at least 1.0ºC above-average across much of the central and east-central equatorial Pacific.
•Based on current observations and dynamical model forecasts, El Niño is expected to strengthen and last through Northern Hemisphere winter 2009-10.