I can see that price of bitcoin is going up after that dump occurred in the last few days so which might be the time for making our investments on altcoins because looks like altcoins were also just following the path so we will have new all time high price for most of the coins in near future.
Anytime is the best time as long as bitcoin still has not break it's all time high.
Altcoins in general are still cheap, there's only few altcoins that has already rise so far, AFAIK, they are BNB, LTC, and BCH, these are major coins only, there are also a lot of altcoins to consider with great potential, so if you haven't invested yet, try looking around and shop, I tell you they are really cheap and that gives you a better opportunity.
I'm also buying if I still have more money to risk, but right now, I'm just more on holding since I got FOMOd in the past and I like to recover my losses and the only way I see is a new bull run and I will hold until that time comes .