Relative humidity fall crocus

Jane McGary
Fri, 13 Aug 2004 19:10:05 PDT
Regarding dew point, I have never heard this statistic mentioned on our 
local weather reports, but they always mention the freezing point, which is 
an elevation above sea level. In summer this can range from about 6000 to 
15000 feet, roughly. (There are permanent snowfields and glaciers on Mt. 
Hood less than an hour's drive from my house.)

My own land is at 1600 feet asl. Temperatures here are slightly cooler than 
where Dave Karnstedt lives, which I think is about 150 feet. In addition, 
there is more frequent wind here, owing to downslope winds and the 
influence of a major river gorge (the Clackamas River, the one south of the 

In addition, we mustn't forget the "urban heat island" effect. Pavement and 
buildings act as heat "sinks" and release heat over a longer night period 
than vegetated countryside. Nights in a city are hotter than in the 
country. Certain topography can also affect temperature; for instance, the 
little town of Estacada, 6 miles from my home, is regularly hotter, though 
only about 700 feet lower, because it sits at the bottom of a narrow river 

There are plenty more interesting things about small climatic patterns. I 
had the opportunity to work as the copyeditor on the Oxford Encyclopedia of 
Climate and Weather, and can look things up in it for anyone who is interested.

Jane McGary
Northwestern Oregon, USA
Finally cooling off a little today

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