The Annual Wildebeest and Zebra Migration is essentially the movement of thousands of animals across the grassy plains of East Africa (Serengeti and Masai Mara) in search of greener pasture and water due to the change of season
There is no start or finish as such but we commonly say the migration goes from the Serengeti Plains in a north-westerly(grumeti-masai Mara) direction towards the famous Masai Mara Game Reserve. The exact timing and route of the migration changes from year to year - depending on the rains.
The annual rains hit the Serengeti in January or February allowing the female wildebeest herd to start giving birth. By March or April, the area has dried out and become desolate again so the massive grouping of animals are forced to move northwards towards Lake Victoria where they begin the mating season. After this, they head towards the Masai Mara in June or July and this is where most people come to witness the sight of thousands of animals galloping across the plains and fording raging rivers with crocodiles in wait!

Beats me where this first time poster found the information above, but there are errors for sure. Why copying and not knowing from first-hand experience is not very smart.

While it can rain anytime during the year, even during the so-called 'dry' seasons, it's unlikely to have rain in the Serengeti during January & February. Rather the 'long' rains arrive during April & May. The herds actually 'calve' their young in the Ndutu area of the Ngorongoro Conservation Area (NCA) or Southeast Serengeti during January & February.

After the wet months of April & May, the herds head north towards the Central Serengeti, where some head West arriving by June; others head North; with the bulk of the herds in the North by mid-July when about have the millions of animals - wildies, zebra and antelope - cross into the Masai Mara and remain there thru September or even October. Those that do not cross into the Mara remain in the Northern Serengeti till those in the Mara commence their return south to join up and move South again to Ndutu.

What is the point of this post anyway....?

I wondered also, but felt to set it straight for those who might come upon it and not know.

I don't know, rained pretty heavily in January in the Southern Serengeti when I was there. From what I was told this is normal for this time of year. Just saying!

But what the point of the post is, I have no idea either.