I stopped booking flights on Tuesdays after tracking 60 fares from SFO to Austin
Everyone says Tuesday is the cheapest day to book but I kept a spreadsheet for 3 months and the Sunday fares were $40 to $70 lower almost every time. I think it's because the business travelers book early in the week and the airlines drop prices on the weekend to fill seats. I tested it on 4 different routes and the pattern held up on all of them. Try pricing your next trip on a Sunday morning and see if it comes out cheaper for you.