A prediction of the peak sunspot number for solar cycle 23

We use a precursor technique based on the geomagnetic aa index during the decline (last 30%) of solar cycle 22 to predict a peak sunspot number-of 158 (+/-18) for cycle 23, under the assumption that solar minimum occurred in May 1996. This method appears to be as reliable as those that require a year of data surrounding the geomagnetic minimum, which typically follows the smoothed sunspot minimum by about six months.