I've witnessed quite a number of halvings for Bitcoin and various altcoins.
Price rise during halving is possible, but usually only as a rather short term speculation.
I've seen cases where the halving was "priced in" months before it actually happened. I've seen cases halving had effect on price only after months. I've seen cases halving had no effect at all (!).
All in all I'd say that there's no proper rule. Speculation and the entire cash flow in altcoin markets tends to have bigger effect than the actual halving.
But don't take my words for it. Do your own research and invest (or not) your money based on more data and your decisions.