In article ,
Bernard Burton writes:
Hello John, I wonder if you may have mistaken the column marked SL to stand
for sleet. I do not have any statistics for snow verses sleet in that table,
and the SL there stands for 'snow lying'.

Yes, I made that - rather stupid - mistake. Sadly I find that such silly
errors are becoming more frequent as I get older.

Thanks for clarifying.
--
John Hall

"The covers of this book are too far apart."
Ambrose Bierce (1842-1914)