Summer is a season, defined by convention in meteorology as the whole
months of June, July, and August, in the Northern hemisphere, and the
whole months of December, January, and February, in the Southern hemisphere.
The exact start of Summer is a matter of convention: in Ireland it is
as early as May 1; in many countries it is considered to be June 1,
while in many others it is as late as June 21. In general, seasonal
changes occur earlier in coastal regions, so countries close to the
oceans go for an earlier start to Summer than continental ones. Summer
is commonly viewed as the season with the longest (and warmest) days
of the year, in which the daylight predominates, through varying degrees.
In the northern latitudes, twilight is known to last at least an hour,
sometimes leading to the famous white nights found in St. Petersburg
It is also called the season of the midnight sun near the North Pole;
in Iceland for instance.