Nattyj,

I've seen this in a few places:

The ideal time for airline flights is 171 days prior to the trip for international flights, 57 for domestic flights.

Also Tuesday 3pm Eastern is the best time of the week to book.

I'd check the closest Tuesday to 171 days out and see how that fare is.

As always with airfares, things change, so your mileage may vary.

~Moose