i think best time to invest.... NOW. because tomorrow price will increase. this motto is able for all days. TTM.
It's just a prediction and also bitcoin will not always increase sometime bitcoin will fall so we have to choose the right time but to invest bitcoin is very not recommended for now because the current price is very high
i am talking from previous few weeks when the price of bitcoin was trading below 1270 USD that in recent time the price of bitcoin is expected to increase more and more and very soon the price of bitcoin will start increasing and now we can see that the price of bitcoin is trading above 1300 USD level that is really a very heavy price.
Bitcoin price reach $1300 right now and I've ever heard ; don't buy bitcoin at ATH when all of the people talking about it because it may drop back after that. But, we don't know whether current price will increase, stable for a while or wait for another decrease. So, it depends on your own decision as Op stated the best time maybe today with the information you have, bitcoin price will always rise anyway.
Yes, be smart and don't fall for the news, the ATH is just a good news for holders and also a signal for those bag holders because that one of the right time to unload their few bitcoins from holding. Bitcoin price have a potential to grow up even more but it is better and wise if we don't buy at the ATH price of bitcoin because there is more chance of getting loss than profit.