[uncountable, countable] the warmest season of the year, coming between spring and fall We're going away in the summer. It's very hot here in summer. in the summer of 2011 late/early summer this/next/last summer a cool/hot/wet summer It is now high summer (= the hottest part of summer). a summer's day a summer dress the summer vacation two summers ago see Indian summer
Idioms you must not take too seriously a small sign that something is happening or will happen in the future, because the situation could change See summer in the Oxford Advanced Learner's Dictionary