What do the lines in this NASA graphic represent?
Why does Solar cycle 22 have a peak of nearly 300 (assuming that peak represents the maximum observations at the same time) and this link says the peak is 212)?
In the above plot by Hathaway, the jagged line peaking at 284.5 in June 1989 is the monthly international sunspot number. The smooth curve starting and ending a few years later is a prediction based on recent observations and statistics of past cycles.
The peak of 212.5 in November 1989 is for a 13-month smoothing of the monthly number. The Sunspot Index and Long-term Solar Observations (SILSO) project at the Royal Observatory of Belgium archives these data and provides this plot of the monthly and smoothed sunspot numbers together.