There is no specific time for this one, anything can happen in a day and it's hard to say that can't guarantee that. If you trade, make your time frame a little longer and use indicators to anticipate future trends, but never expect it to happen completely, keep track of market price trends.
Monitoring market price trends will also not help much unless you also monitor all news about cryptocurrencies that can have an effect on the market and cryptocurrency prices in the market, so not only timing is needed in terms of trading, but several other things that can support trading as well needed.