Started twice in May, wore trailrunners and was fine. Both times I had very little rain. Yes, there is a chance with weather what it is nowadays, that it will be raining for extended periods of time and that the way will get very muddy. And boots work better in conditions like that. But then i personally found that trailrunners worked that much better for me and that said risk was rather small and in the worst case i can buy muyself a pair of boots. So thats how i made my choice. I try not to pack for every thing that CAN happen but only for things that WILL (most likely) happen. Having a rough idea about what to do in a szenario you're not prepared for and having a few extra bucks does certainly help.
(For example my rain gear is not made for walking in hours of hard pouring rain. So in the unlikely event i would maybe cut my day short or even spend an extra night somewhere or, if available, just buy a poncho)