The best time to buy was several years ago. The second best time is now.
I'm pretty sure that bitcoin will reach another highest value in this year. Imagine if Chinese exchanger also operated once again afer being regulated , this will be a great / positive toward bitcoin value.
I'm usually spend my monthly salary for investing bitcoin without any doubt because I've trust bitcoin over 3 years and keep counting until now
Technically, patience is the key on buying coins for investments. Due to the ICO ban on China, large bitcoin trading platforms are slowly closing their operations and its impact to the bitcoin liquidity may be felt like 1~2 months from now. Due to bitcoin's volatility, it is difficult to predict the price by just looking at the chart history but you can infer that there has been a steady increase in these past few days. The best time might be now, or even next month but you need to establish your goal, either for short-term or long-term investments.