The maximum of this next cycle – measured in terms of sunspot number, a standard measure of solar activity level – could be 30 to 50% lower than the most recent one.
The new research was led by Irina Kitiashvili, a researcher with the Bay Area Environmental Research Institute at NASA’s Ames Research Center, in California’s Silicon Valley
(Though they got the last cycle prediction spectacularly wrong)
There's an interesting discussion in the comments section..
Leif Svalgaard predicted that cycle 25 would be higher than 24, but lower than cycle 20.
And I've already posted Zharakovas prediction..