Alastair wrote:
On Jul 15, 11:11 am, "peter clarke" wrote:
Following Keith's earlier thread, more evidence has accumulated. The late
Colin Finch- one of the founder members of COL , and the only person I have
ever met who spent Saturdays in the 1960s and 1970s plotting a northern
hemisphere chart from morse code transmissions on a shortwave radio -
produced a formula for predicting late summer temperatures. Briefly, if the
second week of July( 7-14th) failed to produce at least 2 days with the
temperature reaching at least 24c in his part of Surrey, then there
wouldn't be many more in the weeks leading up to the end of August. I'm sure
he wrote this up for a COL bulletin in the 1970s; no doubt someone here
will have a copy.

I find myself checking the daily max temperatures every year at this time
of July. There were NO days with 24c here between the 7th and 14th, and
there were none last year or in 2007. We all know how the late summers
turned out. Going back through my temperature records since 1970, I found
that there were 12 years when 24c failed to be reached in the critical
week. The 6 weeks which followed produced an average of 9 days with at least
24c.. By contrast, in the years when 24c was achieved on at least 3 days
between the 7 and 14th, the next 6 weeks produced an average of 21 such
days.

In 5 years there were 7days above 24c in the critical week ( 1976, 1983,
1995, 1997, 1999) . The average number of similar days in the following 6
weeks was 29.

Peter Clarke
Ewell,Epsom

Interesting, today is St Swithun's Day.

Cheers, Alastair.

I usually go on the fact that whatever the weather does on St Swithin's
Day, is usually the type of weather we'll have until the beginning of
September.