Stain deck now or wait until Spring?

I'm in Minnesota, and winter is approaching. My deck is entirely unstained/unsealed. I'm planning to use a semi-transparent stain like what's recommended on this site.

My deck was built in 2 phases: most of it last summer (1 year ago), and the railings this summer.

So all the deck surface boards have gone through 1 year of weathering. I would much prefer to wait until Spring to stain... I'm concerned that time and weather will not permit me to prep & stain properly before it gets too cold.

Would it be risky to wait until Spring? The decking has not suffered damage per se, just greying. When Spring comes, the decking will be about 20 months old and gone through 2 Minnesota winters. Is that too risky?

I've just scrubbed the decking using a hard bristle brush and water (no chemicals yet), and lots of grey grime came up, revealing something closer to the original wood color (this is red cedar). Will this allow the decking to weather the winter a bit more safely?

In the Spring I'm willing to scrub again, sand (which I haven't done), brighten, whatever.