if you look at things retrospectively, the conclusions can be drastically different. a month ago, it was a great time to buy bitcoin and steem, not anymore. and i was just looking at the charts for btc, i think a big move is on the way, buy volumes are low and price has stagnated. we could have another down move that takes btc to 2500. or even lower 1800. but then the same can be true for the upside.
the best time to buy steem is when you have money to buy steem and want to increase your stake. there is no way to tell what the price will be tomorrow. if you are a trader and can take an educated guess about the market then decided, else if you want to increase your stake and are looking for someone to tell you when to do so, please don't do that. because even some of the best traders can end up losing money. past performance is not an indication of future returns. each call is a new one.
think about the risk, think about the upside and invest only when you are ready to see steem at 1 cent. if you are ok with that, then buy whatever volatile currency you like. if you believe in crypto, then keep buying small amount every month. that ways you average down and don't have to worry about what is the best time.