Sentence:  It is significant that the Catskills , which used to be the summer playground for older teen-agers , a kind of <WSD>summer</WSD> suburb of New York , no longer attracts them in great numbers - except for those who work there as waiters , bus boys , or counselors in the day camps . 
Meaning of the word marked with <WSD> tags:  the warmest season of the year; in the northern hemisphere it extends from the summer solstice to the autumnal equinox