On 2009 Jun 29, at 11:49 , MIKE OSSIPOFF wrote:
But, in general, in the temperate zones, all the record books that I've looked at show a lag that nearly always varies between about .75 months and 1.75 months.
Irv replies: Mike responded to an earlier message that I subsequently corrected (where the subject heading ends with "Oh YES there is").
Since posting that correction, I have repeated the analysis using solar declination instead of solar longitude.
For Toronto, a 35-day lag yielded a good sine-wave fit to the average daily temperature.
For the purposes of such a chart, the difference between solar longitude and solar declination with respect to the timing of the equinoxes and solstices is negligible.
It was easier to do the sine-wave fit to the solar longitude because it so happens that the solar longitude increases by almost one degree per day.
Yesterday I spoke to an experienced meteorologist from Montreal, who happens to have done his PhD on this subject. His thesis included expressions for variation of the seasonal average temperature with latitude and longitude and elevation. He says that in Montreal the typical lag was 30 days -- that city is further north than Toronto, closer to the Atlantic, and adjacent to the semi-salty St. Lawrence Seaway (Toronto is on the north shore of Lake Ontario, but that is fresh water). He also pointed out that the seasonal "blips" where warm weather happens just before the coldest days, and where cool weather happens just before the hottest days, are calendrically amazingly reproducible.
I could look at some other cities in my plot and sine-wave fit, but so far nobody has suggested a city to try -- Mike, how about your city, where do you live?
-- Irv Bromberg, Toronto, Canada
