Specifically the "Each time the seasons change, you gain +100% chaince to critical with your next spell, and its spell points cost is one tenth its normal cost" part.
Spell point cost does not get reduced. I thought it'd be cool to use it for a maximized empowered Storm of Vengeance (the non-SLA one) since the cost is in the 80's, I think.
Not a game-breaker but it'd be cool if it worked.