The delayed onset of Solar Cycle 24 over the past year stymied the group of solar physicists as sunspots from the previous cycle recently appeared long after some associated with the new cycle had emerged.

The panel now expects solar activity to peak about a year late in May 2013, when Earth’s star will sport an average of about 90 sunspots each day.

Even with a relatively mild period of solar activity, large solar flares and accompanying geomagnetic storms could still occur with enough force to knock out power grids and Earth-orbiting satellites, the scientists cautioned.

“If there are fewer storms, they could still be just as intense,” said panel chair Doug Biesecker of the National Oceanic and Atmospheric Administration Space Weather Prediction Center in Boulder, Colorado.

Solar image: Solar and Heliospheric Observatory (SOHO)