There is no specific time to invest. You can invest whenever you want using DCA method.
The right time to invest is when you have seen that you have your discretionary income ready, Bitcoin investment is a long time investment so its not what you should invest with money you can't afford to loss so a specific time to invest is when you have a leftover income which is your discretionary.
Secondly waiting for the price of Bitcoin to dip before accumulating is a trader strategy and target when there is an increase to sell Bitcoin is a volatile asset it might still dip while waiting to increase to sell so it's always best to accumulate Bitcoin and hodl for long always keep accumulating and hodl, the DCA is guild to regularly accumulate Bitcoin weekly or monthly regardless of it's price and hodl for 4-10 years.
In no case should you wait for the price to fall or rise, this is already an attempt to become a trader. But in reality, no one knows whether the price of Bitcoin will rise or fall tomorrow.
We should not wait and guess, you just need to invest constantly and maintain investments. I mean, we cannot invest today according to the DCA, and in a week, due to everyday needs, transfer money to fiat, because we wanted to buy something.
This is not investing, but deceiving ourselves. And I am sure many do this due to weakness of character. This cannot be allowed.
Strength of character and the ability to not change of our views will be rewarded.
Waiting for a dip is always a bad idea, We might not only be waiting for a dip probably there must be different reasons why we tend to be waiting to start investing in Bitcoin, but we should not decide to be waiting for a dip all because we want to buy Bitcoin at a low price, this process we should be well aware of missing out on opportunities that might come with accumulating Bitcoin consistently and no matter what happens we should always endeavor to buy Bitcoin on a regular basis when we have the DCA to always buy and accumulate Bitcoin which ever time we want considering that we’ve a discretionary amount to buy Bitcoin, I just think that as a newbie or pleb who wants to buy and invest into Bitcoin and we should mostly consider having a discretionary income before we would be talking about investing into Bitcoin.