Astronomically, this is the period between the summer solstice and the autumnal equinox. It is characterized as having the warmest temperatures of the year, except in some tropical regions. Customarily, this refers to the months of June, July, and August in the North Hemisphere, and the months of December, January, and February in the Southern Hemisphere.
SUMMER
Meaning of SUMMER in English
Weather and meteorology English vocabulary. Английский словарь погоды и метеорологии . 2012