I’d love to be able to start on my Draenie Shammy sooner rather than later and so i’d like to think that the pre-patch will begin in a month or so.
Hopefully beta will be concentrating more on getting the raids running correctly and the likes of the new race zones are nearly ready to go 
We don’t have beta yet. Prepatch won’t start in a month. Prepatches are usually 3-5 weeks before release. I think the game will release in the summer so prepatch most likely also summer.
The earliest date suggested by a “leak” is PTR in March, prepatch in mid-April and release in early May. This would be in line with Naxx release being 1 month ahead of the vanilla naxx release (as compared to launch), and thus be 2 months ahead of “vanilla” TBC launch in Europe. I find it perfectly feasible, if slightly on the rushed side.
I just don’t see them releasing an expansion in the middle of summer.
I don’t think it will come until mind June to be honest, with TBC a month later.
Okay so, let me break it down for you peeps.
Facts:
Pre-patch will need to be at least one and a half or two months long for the “hype” and “build up”.
Picture it like this: Blizzard puts a long pre-patch, TBC is officially out without TBC being out = Money.
They’ve done this numerous of times, you’ll get Pre-patch (TBC without Outland content) out and a message “The Dark Portal opens on ___”. You’ll bite it and be happy about it.
Hope this helps.
I think it ill be quite longer, because Blizz ould give time for people to level up Blood elves/Draenei.
They said that beta will be “soon” iirc.
Pre-patch and Beta testing are two entire different things. One is the underlay for TBC, while the Beta resembles raids, Outland content and so on.
My guess is:
But what do I know…
But they need to beta-test prepatch too. There are so many mechanics, new spells, changes in all fetaures, and they all need to work properly. I highly doubt that the classic team is capable of testing prepatch on themselves without the community input.
You gotta remember that we this time around are getting an expansion that, largely, is already developed… That can automatically r educe the time between prepatch, release etc by alot.
It is unquestionably less to test than Classic vanilla but everything needs to be manually checked for for weirdness like the bug they mentioned in the deep-dive.
It’ll be time-consuming work.
Classic PTR has 1.13.7 already and there is no TBC content in any way, so 1.13.8 maybe
prepatch is 2.0
I think in this case prepatch will be 2.5.0 and release will be 2.5.1
summer
10 caracters
Pre-patch May 4th, TBC two months later.
Classic launched on August 26th 2019 - Mid summer.
Why do you think that summer is unlikely for video game/expansion releases?
Schools are open and vacation is over in late August. That is not mid summer.
The seasons have nothing to do with school or holidays (vacation) - we (humans) based the holidays around nature and not the other way around! 
You seem to be avoiding the question of why you think games will not be released in summer when WoW Classic was launched in summer, in favour of debating which part of summer August is.
This is a common tactic of people who have been proved wrong - to try and change the terms of the argument to something that wasn’t debated in the hope hat by slyly changing whats being debated it will be glossed over that they were wrong at all. It is called a “Straw Man”:
https ://en.wikipedia .org/wiki/ Straw_man
" A straw man (sometimes written as strawman) is a form of argument and an informal fallacy of having the impression of refuting an argument, whereas the proper idea of argument under discussion was not addressed or properly refuted. One who engages in this fallacy is said to be “attacking a straw man”.
The typical straw man argument creates the illusion of having completely refuted or defeated an opponent’s proposition through the covert replacement of it with a different proposition (i.e., “stand up a straw man”) and the subsequent refutation of that false argument (“knock down a straw man”) instead of the opponent’s proposition. Straw man arguments have been used throughout history in polemical debate, particularly regarding highly charged emotional subjects."
Straw man… Isn’t that what you’ve just done?