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 num
ber-of 158 (+/-18) for cycle 23, under the assumption that solar minim
um occurred in May 1996. This method appears to be as reliable as thos
e that require a year of data surrounding the geomagnetic minimum, whi
ch typically follows the smoothed sunspot minimum by about six months.