I agree that that is too short notice.
But, the notice period aside, it is difficult to please all parents. For some, 1pm would be ideal and they might find the traditional evening appointments very difficult.
The school I work at publishes a term diary at the start of every term and has a newsletter every week. As much as possible goes in at the start of term but we have to submit everything to the secretary by half way through the previous term for it to get back from the printers in time so there are sometimes omissions and changes. We tried to do for an online, editable diary (which we use internally) instead but the parents didn't want it for some reason and voted overwhelmingly for the hard copy.
I think parents need to appreciate that a) every event is an invitation and not compulsory and b) we have to try and balance the differing needs of different families.
Our parents evenings run from 6pm to 9pm on a choice of 2 different nights with parents welcome to turn up at any time during that window and a crèche provided. But there are still many who would prefer daytime, I'm sure.
Our assemblies, informal concerts and house drama/music/dance/sport events tend to be day time because they are just part of the school day. We don't want children doing them after school and we don't need (or necessarily even want, depending on how low the standard has turned out to be
) parents there but some get upset not be given the option to attend everything that happens.
Larger productions, concerts, sports days, formal events etc all tend to be evening or weekend affairs because the school actively want as many parents as possible to come. But it's still not assumed that all can.