When did the last solar flare happen?

Answer 1

There are generally solar flares every few days, and almost always within a week or so. Really spectacular flares are more common during the "Solar Max" period around the peak of the sunspot cycle. That will be in 2013 or so. You can see recent movies of solar flares and prominences at http://thesuninmotion.com/

Answer 2

Solar flares are explosions and eruptions on the Sun itself, so they are all about 93,000,000 miles away. A big solar flare can cause a Coronal Mass Ejection, which is a cloud of highly-charged solar particles that escape from the Sun completely. CMEs routinely strike the Earth causing solar storms, auroras, and occasionally damage to electronic equipment on Earth or on orbiting satellites.

Right now, the Sun is in an extended - almost eerie! - period of dormancy following the last Solar Minimum. The next solar cycle ought to have started 18 months ago, but as of August 22, 2009, the Sun has been without sunspots for the past 40 days. And there is at present no sign of renewed activity. This is not dangerous, but is a little disconcerting to astronomers. It's been 100 years since the Sun was this quiet for this long, and an extended solar minimum may have effects on the Earth's weather as well.

Answer 3

There are solar flares almost every day. There were a couple of very impressive solar flares on June 16, 2010; see the link below for a neat movie of it.

Answer 4

Individual solar flares can't be predicted.

All we can say is that the level of solar activity, including flares and sunspots,

varies in a cycle that averages around 11 years.