It is possible but some days will just have to fall outside of the regular months. It's not perfect but perfect is impossible and it's much better than having months of random duration like the Gregorian calendar has because every month is equal and the "year day" and "leap day" can just be made holidays. Also, with equal months weeks can properly fit into months. E.g. every month could start on a Monday and end on a a Sunday. It would also make bookkeeping easier.
International Fixed Calendar is really nice, but it has no chances (it has even less than constructed languages for international use).
Really it is very easy to understand/remember actual calendar format, so there is no need to change it. Even, if you change it. it would be really crazy ans costly: when you use it you must have all modified. Have you though all code would need to be changed? Plus code you can't change?
For example, my venerable HP-48 series calculators have clock/calendar and date functions, and I would lost it
(Just joking, but I love that machine, and I use actually).
A constructed international auxiliary language (like Lojban) can be introduced as one more language: you don't need to speak it that day, and if pushed it would get more and more int' use over time (at some time it could be studied like 2nd language in schools), even some people won't be interested in international language (they don't need it as they don't need to communicate internationally). And that have near zero chances. Int' fixed calendar has less chances of being adopted, but much higher cost than int' aux language, while you gain too little with calendar change.
With Lojban we would gain a lot of: regular but powerful int language, clear rules, exact pronunciation, regulated, neutral and equal for all (no one is native speaker on it). We'd gain much more than with new regular calendar, but it has no chances.