The below quoted comment seems reasonable but I believe is incorrect.
First it is written entirely from a northern hemisphere viewpoint.
Second it takes too narrow a view of what is happening.
Let us simplify. Consider a relatively small area in the mid latitudes of
the northern hemisphere in the days around the summer solstice. At sometime
before the summer solstice more solar energy will arrive during the day
than is lost during the night. The temperature will start to go up. At the
solstice the additional day time energy will still cause the temperature to go
up. Sometime after the solstice the nighttime energy loss will become
larger than the daytime gain. Only then will the average temperature start to
go down.
The thermal mass of the earth will have an affect on just when these
turning points occur but it is not the major determinant.
Alex. F. Burr
In a message dated 4/23/2011 2:52:40 P.M. Mountain Daylight Time,
Anthony_Lapinski@pds.org writes:
The hottest days are about a month after the
summer solstice, and the coldest days are about a month after the winter
solstice. This "thermal lagging" is due to the large mass of the Earth and
the time it takes it to cool/warm