When tracking airfare prices for a particular destination, deciding when to book can be difficult. Book too soon and you risk missing out on a lower price, but book too late and fares may rise by hundreds of dollars. I posed your question to representatives from two major online travel agencies to get their advance-booking tips.
Hotwire offered the following guidelines: Book April and May flights at least three to eight weeks in advance, June and July flights six to eight weeks in advance, and August and September flights three to eight weeks in advance.
In addition, “While airfares in August are traditionally more expensive, hotel stays are far more affordable, making August a surprisingly good option.”