NASA has updated its forecast for Solar Cycle 24.
Maximum is expected to be reached in Spring 2013 with a sunspot number of 60 and this prediction is for the lowest sunspot number in 100 years. This only confirms that we are currently in a solar minimum – the Landscheidt Minimum – though it remains to be seen whether this will be a Grand Minimum in the style of the Maunder Minimum or the Dalton Minimum. In any event a period of several decades of global cooling is to be expected and is already probably upon us (starting some 10 years ago).
Updated June 5th 2012:
The current prediction for Sunspot Cycle 24 gives a smoothed sunspot number maximum of about 60 in the Spring of 2013. We are currently over three years into Cycle 24. The current predicted size makes this the smallest sunspot cycle in about 100 years. .. Using data for the current sunspot cycle indicates a starting date of May of 2008. ..
… to produce a prediction of the monthly sunspot numbers through the next cycle. We find a maximum of about 60 in the Spring of 2013.
Another indicator of the level of solar activity is the flux of radio emission from the Sun at a wavelength of 10.7 cm (2.8 GHz frequency). This flux has been measured daily since 1947. It is an important indicator of solar activity because it tends to follow the changes in the solar ultraviolet that influence the Earth’s upper atmosphere and ionosphere. Many models of the upper atmosphere use the 10.7 cm flux (F10.7) as input to determine atmospheric densities and satellite drag. F10.7 has been shown to follow the sunspot number quite closely and similar prediction techniques can be used.