"ronaldbutton" wrote :

I've been studying the facts and figures on my new website woodford wells
weather this morning and have noticed that sunrise today 06.05 and sunset
is 18.12.ie a difference of 12 hours 7 minutes.
If the equinox is not until the 21st, how come ?
As ever,prepared to put my head above the parapet,

Refraction, Ron. You know that when you put a knife half in
and half out of a glass of water the knife looks as though it's bent
at the boundary of the air and the water. Same thing happens in
the atmosphere. At sunrise you see the sun a few minutes
before it's actually there ( and the opposite at sunset). No doubt
others can be more specific, but in our latitude it adds about
3 or 4 minutes to the time we can see the sun at both sunrise
and sunset. It also means that, horizons permitting, at the
two equinoxes the sun is above the horizon -- just -- for 24 hours
at both the North and South Poles.

Philip