Warmest Days of the Year for the U.S.

See the link for maps.

Note that the date range where the highest temperature s likely to occur is not exactly the same as the date range where the maximum DAILY AVERAGE temperature normally falls.
He defines DAILY AVERAGE temperature = daily normal temperature = normal high plus normal low divided by two.

http://www.wunderground.com/blog/weatherhistorian/comment.html?entrynum=289

By: Christopher C. Burt , 5:35 PM GMT on July 09, 2014

NOAA recently produced an interesting map showing when the hottest day of the year is likely to occur in the contiguous U.S. Complimenting this map is one produced by Brian Brettschneider of Borealis Scientific, LLC, which illustrates the date of summer’s midpoint (peak of summer average temperatures) ••• Brian has also produced maps of such for the Fall, Winter and Spring seasons. There is also some other great material from Brian herein.

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