The CDC is saying to get the flu shot near the end of October, though. I can understand not getting it in July/August but now seems about as good a time as any.The effectiveness declines over time because of the shrinking antibody population. If you take it now, it will be way less effective by the time the flu season peaks. Flu season is shifting a lot, more to January and February nowadays. So recommendation is to get the shot more towards the end of November. So if you take it now, you get a nice false sense of security.
My wife dispensed her first xofluza last week so I'd say between now and the next two weeks would be the best time. Of course it's totally situational based on location but still.