This sort of combination tends not to happen much after about the
beginning of April, because, I imagine, the strength of the sun rises
temperatures to above average levels by default even if the air mass
is cold. The required conditions for such a combination seem to be a
reasonably strong wind from a cold direction (typically NE) plus high
pressure. This year we did have a late cold sunny day on the 4th in
Hampshire, with tempeature no higher than 12C, a typical March value
these days.

I also remember a similar windy anticyclonic NE period in mid May 1996
when the temperature was around 14C, 3C below 'old' normal values and
perhaps 4C beyond post-1989 mean May max temps. But has there been any
later? I was thinking next week might be a good setup but cold highs
tend to be cloudy through the months of June,July and August.

On a related point, when's the latest occasion of warm, sunny weather?
I remember some warm sunny days in early November in one or two years,
and some in mid January but never in December.

By sunny I mean settled conditions where the sunny conditions are
widespread BTW, rather than localised (e.g. coast or mountain)
effects.

Nick

On Jun 18, 10:31 am, wrote:
This sort of combination tends not to happen much after about the
beginning of April, because, I imagine, the strength of the sun rises
temperatures to above average levels by default even if the air mass
is cold. The required conditions for such a combination seem to be a
reasonably strong wind from a cold direction (typically NE) plus high
pressure. This year we did have a late cold sunny day on the 4th in
Hampshire, with tempeature no higher than 12C, a typical March value
these days.

I also remember a similar windy anticyclonic NE period in mid May 1996
when the temperature was around 14C, 3C below 'old' normal values and
perhaps 4C beyond post-1989 mean May max temps. But has there been any
later? I was thinking next week might be a good setup but cold highs
tend to be cloudy through the months of June,July and August.

On a related point, when's the latest occasion of warm, sunny weather?
I remember some warm sunny days in early November in one or two years,
and some in mid January but never in December.

By sunny I mean settled conditions where the sunny conditions are
widespread BTW, rather than localised (e.g. coast or mountain)
effects.

Nick

An interesting point, all this. It can happen in summer with
a cool NW'ly as well as with a NE'ly. I think there were a number of
days in the unusual August and September of 1986 that were sunny and
cool, and also in the dry cool summer of 1972. As to warm, sunny
December days they do seem rather rare maybe because the sun is at its
lowest and of course for the obvious reason that in winter mild days
are associated with cloudy Tropical Maritime air. What seems to be
needed is a retreating transient ridge with a gentle SW'ly. Christmas
day 1954 fulfilled this, I seem to remember and for me, even at the
age of 12, put the final nail in the coffin containing the romantic
notion the Christmas ought to be snowy. Nasty clever little boy. :-(

Tudor Hughes, Warlingham, Surrey.