Bitcoin is a very volatile currency, but the trend lately is undeniably upward, and that trend will likely continue over the near term as adoption increases and (more importantly) as people in countries with less stable economies find that they can protect their assets by investing in bitcoin. Indeed, serious economic disruption in parts of the world seems to lead to a temporary spike in the price of bitcoin.
The big caveat here is the fact that bitcoin itself is very much subject to the uneducated whims of the market, especially as bitcoin-related businesses fall victim to security lapses, which the media tend to report as bitcoin itself being hacked. These stories are often followed by temporary drops in the value of bitcoin.
As it is, I think that a long term investment in bitcoin is very sound. And by long term I mean one to two years.
As far as very short term speculation goes, the big mystery is what will happen later this week with the halving of the bitcoin mining reward rate. Exactly what that is is complicated, and you should google it. But suffice it to say, some predict the price of bitcoin is going to jump way up in response to the halving, while others say the impact of that event is already priced into bitcoin. There are still others who say that if the network proves unable to respond adequately to the halving, confidence in bitcoin will fall along with the price.
Personally, I think the crowd's assessment of the impact of the halving is already reflected in the price of bitcoin and as such the impact will be minimal.
Bottom line: buy bitcoin if you plan on holding on to it for at least a year or two.