Re-sand or just brighten?

Hello,

About 6 weeks ago, I did 2 rounds of stripping and sanding of my cedar deck. I thought I would be ready to stain, but since then, there hasn't been more than 2 consecutive days where it hasn't rained (record rainfalls here). The deck has since turned grey-ish; i.e. not the really weathered grey, but definitely not the nice bare cedar colour it had 6 weeks ago. 

My question: assuming we get some dry days soon, do I need to sand it again (I'm hoping not, it's a big-ass deck) or would a quality brightener be sufficient to prep the wood for staining?

thanks!!