In article
,
Len Wood writes:
We have had, and are having, an Indian Summer here in Wembury.
Yesterday's max 23.0C, today's 22.8C.
Average for the last week of Sep. is 17.5C
So we are 5 degC above average. Perhaps my quailfying temp of 2 degC
above average is too low.

Anyone any thoughts on this?

I think that this Indian Summer is more "intense" than most, and that 2
degC is probably OK as a threshold so long as there is prolonged
sunshine and the wind isn't too strong. I think that those factors are
as important as the temperature. If it's overcast, then it won't be
perceived as an Indian Summer even if it's warm.
--
John Hall
"The power of accurate observation is commonly called cynicism
by those who have not got it."
George Bernard Shaw