Flight pricing is heavily affected by seasons of the year, and that's not just summer/winter/autumn/spring. It entails school holidays, religious holidays, events and festivals.
I'm going to get you to be a little interactive here, by asking you to go onto a website you use to book flights and look at flights from Toronto to Krakow (Poland) for the 10th September returning in two weeks with Air Canada. Go on... I'll wait.
Now go back and look at the 11th September returning on the same flight, same destination with Air Canada again. Interesting isn't it? How did it go down $200-300 (this has probably fluctuated by the time you read this, and we know why it's fluctuated, right? (if not, read my post, everything you need to know about booking flights)
The reason for such a jump in one day is because every airline in the Star Alliance considers the peak season to Europe from Toronto to be finished on the 10th of September, no later and no earlier. So once again browsing online, this tool is not really available for you to use unless you fancy browsing every airline for your possible destination over a period of an entire season which could be 3 months. However as a travel agent, this tool is available to us. Online sites have overlooked this to keep to their very effective KISS (Keep It Simple Stupid) theory in place.
The tricky thing here is that some airlines don't have certain seasons for certain destinations and other airlines consider their peak and quiet seasons at different times for various reasons. This weapon is not always going to come in handy as your dates are not always flexible, but every now and then it has saved my clients hundreds by a day or two just because I have this tool at my disposal and I can quickly see which airlines might be about to change seasons around the dates I am searching.
Are your eyes starting to open now? Mine certainly were when I was learning all this. As a result I'll never book online again...I'll only book through travel agents from now on.