The water runs from the beginning of May until the end of October and is almost completely independent of rainfall. The cost is: $15 bucks for a day ($7 bucks on Friday evening), $165 bucks for a season pass or $90 for a season pass after August 1st and $90 for students.
See the <a href=http://geneseewaterways.org/kayaking.htm> Lock 32 home page for more information.