So &quot;astronomical summer&quot; oddly <i>starts</i> with the day that the incoming solar energy is highest in the northern hemisphere? Ok, that explains why it&#x27;s used in English, but really it just uses the same definition! The meteorological calendar just appears to use three months, so that is pretty arbitrary.<p>The most logical definition of astronomical summer and winter imho would have been winter and summer being the quarter-years <i>centered</i> on the summer and winter solstice respectively. Then the astronomical definitions would have been in line with (non-english) language, i.e. mid winter is the shortest day and mid summer is the longest day.<p>&gt; Midsummer is celebrated on the longest day in some cultures, on the solstice in others<p>Aren&#x27;t those the same thing (maybe give or take a day)? Where I live it&#x27;s celebrated on a weekend near the solstice, which makes even more sense because alcohol.