Gimpy, my friend, you can use this three month cycle at any time of the year. I just give example with months of June, July, and August because I know in American system, this is the time of year for build up of kilometers. It is ok to use this three month cycle starting in December if you like.
One problem sport of running have is that terminology mean different things to people all over the world. For example, athletes that I coach, I use words like facile (easy), saldo (steady), medio (mdium), and ritmo (tempo). In Russia terms are different, and in English the words are even more different. So please forgive my poor English because this is not first language for Renato.
I try explain again for you. I have woman that runs 15:20 for 5k. During this three month cycle she runs easy long runs with pace of 6:20 per mile, steady runs at 6:00 per mile, and medium runs of 5:40 per mile, and tempo pace for is 5:20 for each mile. This woman spends many kilometers between easy pace and tempo. Sometimes my friends, the best coaches in the world, they don't take good advantage of this pace that is between easy and threshold. When I read article of some coach, and they say that they believe in the method that is hard/easy, I want to cry for them.
So please remember Gimpy, this pace that is between threshold and easy, it is very very important pace for aerobic development. Don't confuse my words. I do not say for you to run long and slow for 3 months. I say use these paces that I tell you, and you will improve very much. But if you run all training long and slow, you will become a long slow runner. And this my friend is no good.