Volcanologists can't predict eruptions. There is no reliable and tested method that can say that a certain volcano will erupt on a certain day or at a certain time. You might see such things on YouTube and elsewhere on the internet, but they are mostly people making patterns where there are none.
However, volcanologists have been getting much better at forecasting eruption likelihood. Now, that might sound a lot like prediction, but it is not. Instead, it is like the weather: they can offer the chances that an eruption might occur over some time period, like a meteorologist might say that we have a 75% chance of a thunderstorm this afternoon. These volcanic forecasts might only be days or hours in advance on an eruption, but even that little warning means getting out of harm's way.
