I think they're just a bunch of cowards at the best of times really, and clearly in denial about how unpopular they now are. Despite the rumours I just can't see him announcing an election for the traditional time of May because then he'd be the shortest-serving PM since Douglas-Home (with the exception of Truss lol), and I just can't see him wanting to voluntarily give himself that label of failure (nor give up half a year of power unnecessarily). Plus, as people say, their one hope atm is that more time means structural issues like inflation might subside.
But you still have to give a month's notice, so they're going to factor in both the polling date itself and when the campaigning will happen. They're not going to want to hold the election outside of term time, because then you have a bunch of motivated progressive voters spread more evenly around the country rather than concentrated in urban seats. But then when you hit September it's conference season, and as much as it might seem appropriate to announce it then the traditional wisdom there is you don't want an election soon after the conferences because you often get unpredictable media coverage that can cause big temporary dents in your poll ratings - look how this year's went - just as easily as temporary bumps. Don't want to give the media any more excuses to saturate the airwaves with more bad news, or coverage of an event that makes Labour look like a government-in-waiting (like an American-style pre-election convention does).
So then you start to push into late autumn, and into the winter, and one of the few things everyone agrees about 2019 is that it was absolutely miserable running campaigns in the dark and wet of a British winter, let alone how much it interfered with the December pre-Christmas party season for lots of people.
That said: the latest they can dissolve Parliament is December 17th, for an election on January 25th. I think he'll push it that far, because they'll (probably correctly) gauge that most people aren't going to pay much attention to campaigning prep until the new year, and that way you reduce the amount of campaigning time the opposition parties get. Reducing turnout usually helps right parties too, and it's not like they actually care if a few of their older voters break hips slipping on ice.
So yeah - depressing as it is, if we haven't had an announcement by April (or at least some very solid rumours) I'm pretty sure it's going to mean January 2025.
schoolsweek.co.uk
